May 8, 2009 
Let us search for ever larger sporadic palindromes
of the form A^{p} + B^{q} (Sum Of Powers).
won178.htm (new) 
March 21, 2009 
B.S. Rangaswamy presents some nice offshoots
after perusing the latest submission of Peter Kogel
i.e., pandigitals as products of two 5digit palindromes.
won177.htm (new)
won175.htm (update) 
March 15, 2009 
Shyam Sunder Gupta counted and announced on the
Number Theory List all the 21digit palindromic primes.
palprim1.htm (update) 
January 13, 2009 
Farideh Firoozbakht shows some intricate patterns.
leading to squares with only three distinct digits 0, 2 & 5.
threedigits.htm (update) 
November 24, 2008 
Investigator Peter Kogel multiplies palindromes to arrive at a beautiful wheel of pandigitals.
won175.htm (new) 
September 15, 2008 
B.S. Rangaswamy shows some nice Hopping Numerals .
Is this a topic for further theorization ?
won174.htm (new) 
August 24, 2008 
Justin Chan makes nice contributions to various topics
exosquar.htm (update)
circular.htm (update) 
July 28, 2008 
Greg Childers factorized Rsm93.
revfact.htm (update) 
June 23, 2008 
Programmer Daniel Fischer finishes the topic of finding
multipliers k such that n.k is palindromic. He did so by
writing some keen 'Haskell' code.
won36.htm (update)
won96.htm (update) 
May 27, 2008 
Investigator Peter Kogel combines nine & pandigitals by using various operations. Some gems arose from his effort.
ninedig2.htm (update) 
May 25, 2008 
Greg Childers sets a new milestone by factorizing Sm99.
factorlist.htm (update) 
March 31, 2008 
B.S. Rangaswamy relates palindromes with nine & pandigitals using straightforward multiplication by 9. The offspring is a table of 34 nice equations !
won173.htm (new) 
February 16, 2008 
Carlos Rivera's pandigital solutions to Mustonen's puzzle.
won172.htm (update) 
January 2, 2008 
Feng Yuan sent in record Palindromic Squares of odd lengths i.e., with 47, 49 & many more digits.
Palindromic Squares (update) 
December 11, 2007 
Greg Childers factorized Sm94 and Rsm88.
factorlist.htm (update)
revfac.htm (update) 
June 17, 2007 
A pandigital divertimento from Seppo Mustonen
won172.htm (new) 
May 23, 2007 
JeanClaude Rosa presents the 43^{rd} palindrome
expressible as the sum of the squares of two consecutives.
sumsquare.htm (update) 
May 21, 2007 
Milton L. Brown makes a random walk around the
powers of ten and conjectures alongside.
won171.htm (new) 
February 25, 2007 
Michael Bergman faces a ninedigital problem.
won170.htm (new) 
January 11, 2007 
Farideh Firoozbakht adds two smallest base 2 pseudoprimes of lengths 17 & 18 and comments her approach.
won125.htm (update) 
November 11, 2006 
Farideh Firoozbakht found two nice consecutive primes of tautonymic length 4949.
won169.htm (new) 
September 4, 2006 
Carlos Rivera shows some remarkable pandigital curios.
won168.htm (new) 
June 12, 2006 
Philippe Strohl factorized Sm98.
factorlist.htm (update) 
March 4, 2006 
Greg Childers certified a record (34*10^{15768}—43)/9 Plateau and Depression Prime (or PDP's for short)
Greg's proof of this 15769digit PDP combines
stateoftheart factorization with three types of
primality testing and proving (BLS, CHG, ECPP).
This prime has only prime digits, therefore it resides also at
won150.htm (update)

February 25, 2006 
Sean A. Irvine factorized Sm93.
factorlist.htm (update) 
February 18, 2006 
Shyam Sunder Gupta counted and announced on the
Number Theory List the 19digit palindromic primes.
palprim1.htm (update) 
February 2, 2006 
Harvey Dubner retakes the palindromic prime record 10^{150008} + 4798974 * 10^{75001} + 1 Congratulations with this number of 150009 digits !
palprim2.htm (update) 
January 23, 2006 
Sean A. Irvine factorized Sm92.
factorlist.htm (update) 
December 31, 2005 
Paul Jobling and Harvey Dubner each established a new palindromic prime record this month 10^{150006} + 7426247 * 10^{75000} + 1 10^{140008} + 4546454 * 10^{70001} + 1 Congratulations both for your amazing palindromes of resp. 150007 and 140009 digits !
palprim2.htm (update) 
November 12, 2005 
B.S. Rangaswamy's book "Wonders of Numerals"
inspired me to expand on some of the subjects, especially when it deals with palindromes, pan and/or ninedigitals.
won167.htm (new) 
October 25, 2005 
Sean A. Irvine factorized Sm90 and Sm91.
factorlist.htm (update) 
October 24, 2005 
A new property for palindrome 69696.
won26.htm (update) 
October 15, 2005 
Beast's real mark devalued to '616'. Reported by Enoch Haga.
won166.htm (new) 
September 12, 2005 
Sean A. Irvine factorized Sm87, Sm88 and Sm89.
factorlist.htm (update) 
September 4, 2005 
B.S. Rangaswamy from Bangalore, India generated 117 pandigitals from palindromes through Fibonacci iteration.
ninedigits.htm (new) 
August 28, 2005 
Sean A. Irvine factorized the Sm83 up to Sm86 by using GNFS.
factorlist.htm (major update) Philippe Strohl completed factorizations of Rsm80
up to Rsm87
revfact.htm (major update) 
August 27, 2005 
Robert Backstrom factorized the c131 of the 79^{th} Reversed Smarandache Concatenated Number by GGNFS. Rsm78 = 3 * 17 * 47 * p14 * p62 * p69
revfact.htm (update) 
August 3, 2005 
Sean A. Irvine factorized the c139 of the 78^{th} Concatenated Smarandache Number by using GNFS. Sm78 = 2 * 3 * 31 * 185897 * p57 * p83
factorlist.htm (update) 
July 24, 2005 
Peter Kogel investigated more nine digit powers. Some notable results are highlighted at the start.
ninedigits.htm (update) 
June 28, 2005 
Robert Backstrom factorized the c142 of the 76^{th} Reversed Smarandache Concatenated Number by GGNFS. Rsm76 = 53 * p63 * p79
revfact.htm (update) 
May 30, 2005 
What is the relation between 66 and a palindromic circle.
Giovanni Resta's amazing picture will show you!
won165.htm (new) 
May 18, 2005 
Read Peter Kogel's addendum to Nine and Ten digit powers.
ninedigits.htm (update) 
March, 2005 
TurkZeka.Com Aim : was established with a purpose of helping puzzle fans improve their ability of imaging, finding winding key, heading conclusion, finding out hidden properties etc. and also having a nice and useful time. Created by Yilmaz Ekici.
Turkzeka  Puzzle Competition 
March 24, 2005 
Follow John Morse's explanation and discovers with him
why 3816547290 is such a unique pandigital number.
ninedigits.htm (update) 
March 20, 2005 
Robert Hein discovers some important equations for
the construction of all infinite Pythagorean Triples.
won164.htm (new) 
March 8, 2005 
Zakir Seidov puts palprimes between two ones
and collects statistical data from it.
palprim5.htm (update) 
February 27, 2005 
Peter Kogel investigates nine and ten digit squares. Along the way he discovered some fascinating specimen.
ninedigits.htm (update) 
February 20, 2005 
Jens Kruse Andersen contributes some gigantic (prp) primes and lays the foundation for the smallest gigantic semiprime.
WONplate 144 (update)
palprim1.htm (update) 
January 23, 2005 
Zakir Seidov contributes a list of palindromic areas
of primitive Phytagorean triangles (PPTs).
WONplate 163 (new) 
January 16, 2005 
Enjoy Hugo Sanchez' latest presentation of
Sumas Palindromizadas con Factores de Corrección.
Naturales del 1 al 100.
WONplate 162 (new) 
January 10, 2005 
Nearest (probable) primes bordering powers of ten
situated at equal distances... (by pdg)
and all three with palindromic displacements so far!
WONplate 161 (new) 
January, 2005 
PuzzleUp is a new weekly problem and games website that is set to launch on January 2nd 2005 and which will consist of 50 individual problems over a one year basis. Created by Emrehan Halici.
puzzleup  weekly puzzle competition 
December 16, 2004 
JeanClaude Rosa explains why there are no 18digit palindromic products of two ninedigitals.
twonine.htm (update) 
December 15, 2004 
David Broadhurst found a nice addendum to Nelson Mandela's prison number 46664 in the form of a palindromic (probable) prime.
won154.htm (update) 
November 24, 2004 
Harvey Dubner establishes again a new palindromic prime record 10^{130022} + 3761673 * 10^{65008} + 1 Congratulations with this number of 130023 digits !
palprim2.htm (update) 
November 18, 2004 
Sean A. Irvine factorized the c133 of the 75^{th} Concatenated Smarandache Number by GNFS. Sm75 = 3 * 5^2 * 193283 * p47 * p87
factorlist.htm (update) 
November 512, 2004 
New Palindromic Subsets of Concatenated Prime Sequences were found by G. Resta, J. K. Andersen and F. Firoozbakht in Carlos Rivera's Puzzle 289.
palconca.htm (update) 
October 18, 2004 
Two Prime Numbers starting from 18 and 19 lead us to the list of Concatenated Smarandache Numbers that are Probable Primes (by Farideh Firoozbakht)
won160.htm (new) 
September 20, 2004 
Andrei Cucuianu (from Romania) demonstrates two
properties of numbers and their reversals. Another 9/11 story...
won159.htm (new) 
September 2, 2004 
Extracting palindromes from Pi (e.g. 7446447 & 110000011). A puzzle/question by the late Klaas Craye.
won158.htm (new) 
August 15, 2004 
Find larger and larger palindromic primes
dividing numbers of the form k.b^{n} ± 1.
won157.htm (new) 
August 7, 2004 
A palindromic formula by Paul Oliverio. Check it out !
won156.htm (new) 
June 28, 2004 
A 3*3 antimagic square composed of primes with
sums in a prime arithmetical progression cannot exist.
WONplate 132 (update) 
April 6, 2004 
Let's acclaim Harvey Dubner's latest palindromic prime record 10^{120016} + 1726271 * 10^{60005} + 1 Congratulations with this number of 120017 digits !
palprim2.htm (update) 
March 23, 2004 
Philippe Strohl completed the factorization of the 73^{th} Concatenated Smarandache Number by GMPECM. Sm73 = 37907 * p46 * p87
factorlist.htm (update) 
January 3, 2004 
Alexander Kruppa and Paul Leyland need to give up ! They have done 5500 curves at B1=11M, and 9000 curves
at B1=44M, but have been unable to find a factor of
the c204 of HP49(100).
Home Primes (update) 
December 30, 2003 
Philippe Strohl completely factorized Rsm_67 ! The next "unknown factorization" for reversed
smarandache concatenated numbers is now Rsm_76.
revfact.htm (update) 
December 26, 2003 
David Broadhurst announced once again a record
palindromic prime (36401 digits) composed solely
of prime digits.
WONplate 150 (update) 
December 1, 2003 
not merely a date... 46664, not merely a palindrome...
December 1^{st} is worldAIDSday... 46664 is a vital campaign...

More at WONplate 154 
November 25, 2003 
Dw discovers more palindromes in the concatenated
string of consecutive prime numbers.
palconca.htm (update) 
November 3, 2003 
Enjoy Hugo Sanchez' presentation of
Patrones Palindrómicos con
Multiples Operaciones Aritméticas.
WONplate 153 (new) 
October 20, 2003 
Ninedigital expressions Fourteen # variations have been statistically analyzed. Can you discover additional curiosities or interesting facts ?
ninedigits.htm (update) 
October 13, 2003 
Tautonymic numbers Introducing a new class of recreational numbers.
WONplate 152 (new) 
September 1, 2003 
Allan Jenks presents his intriguing problem
Recurring last digit multiplication numbers.
WONplate 151 (new) 
August 5, 2003 
David Broadhurst
announced via the Number Theory List a record palindromic prime (30913 digits)
composed solely of prime digits.
Details via WONplate 150 (new) 
August 2, 2003 
Patrick De Geest completed the certification for a record Plateau and Depression Prime (or PDP's for short)
Patrick prime proved a 3037digit PDP using Primo 2.1.1 3(2)_{3035}3 or 2*(10^{3037}1)/9 + (10^{3036}+1)
taking him ~171 hours on a 3000 MHz Intel Pentium 4 cpu. 
July 24, 2003 
Philippe Strohl found all the factors of rsm65
Reversed Smarandache Concatenated Numbers (update) 
July 21, 2003 
Hisanori Mishima revised his page
Chapter 2. Squares consisted of 3 different digits
The search range has now been extended from 10^{17} to 10^{20}. There are 70 new sporadic solutions added to the list.
Entries 013 and 678 still remain without solutions.
Squares containing at most three distinct digits (update) 
July 16, 2003 
Alex Kruppa & Paul Leyland
completed a few more stages of the search for HP49. They successfully factored HP49(97).c151 into p55 * p96 after intelligent teamwork. Method & prime factors can be found at the Home Primes page.
HP49(98) and HP49(99) factored easily under ECM. The 100^{th} step, however, appears to be not so easy! HP49(100) 3 * 37 * 2789 * c204
Paul and Alex think this 100^{th} step will mark the end of the HP49 sequence expansion for a long time to come... 
July 11, 2003 
Hans Rosenthal found (prime proved) a new 6959digit Smoothly Undulating Palindromic Prime (SUPP for short)
3(23)_{3479} = (32*10^{6959}23)/99
It took Hans around 18 months (!) to finish the proof.
He thereby also established a new Primo ECPP world record !
See http://www.ellipsa.net/primo/record.html 
June 21, 2003 
Jeff Heleen just completed the certification for a new Palindromic Wing Primes (or PWP's for short)
Jeff prime proved a 5867digit PWP using Primo 2 Rank 2nd at that moment ! (1)_{2933}7(1)_{2933} or (10^{5867}1)/9 + 6*10^{2933}
taking him ~3406 hours on a 1.33GHz Athlon box. 
June 17, 2003 
Dw found again a new record binarydecimal palindrome ! A milestone, as he passed the magic 100 digit length. 10 1010110011 0000010011 1100000010 0001000111 1010010111 1010010111 1000100001 0000001111 0010000011 0011010101 3390741646331381831336461470933 The binary palindrome contains 102 digits ! The decimal string contains 31 digits ! nobase10.htm 
May 21, 2003 
Dw found a new record binarydecimal palindrome 1 0100110010 1111101111 1100001110 1100100000 0010001000 0000100110 1110000111 1110111110 1001100101
1609061098335005338901609061 The binary palindrome contains 91 digits ! The decimal string contains 28 digits ! nobase10.htm 
May 4, 2003 
Two primes for a square please. A simple search puzzle... with hard to find solutions !
WONplate 148 
April 27, 2003 
181, 313 & 545 are the only PDP's equal to
(plateau and depression primes)
the sum of the squares of two consecutive integers.
(181 = 9^{2} + 10^{2})
(313 = 12^{2} + 13^{2})
(545 = 16^{2} + 17^{2})
WONplate 147 (new) by Jean Claude Rosa 
April 13, 2003 
Dw found a new record binarydecimal palindrome 1010010001 1101011100 1110010101 0010100001 0100000010 1000010100 1010100111 0011101011 1000100101 795280629691202196926082597 The binary palindrome contains 90 digits ! The decimal string contains 27 digits ! nobase10.htm 
February 16, 2003 
A threefold (probable) PRIME search.
WONplate 146 (new) 
January 27, 2003 
Daniel Heuer announced a new PWP world record (#3033).
10^{104281}10^{52140}1 has over 100000 digits...
the largest ever base10 palindromic prime !
ps. exponent 104281 is itself prime.
Palindromic Wing Primes (update) 
January 26, 2003 
Plateau & Depression Primes
(or PDP's for short) are numbers that are primes, palindromic in base 10, and consisting of an internal repdigit sandwiched by a pair of identical digits different of course from the repdigit itself.
Plateau and Depression Primes Everyone is invited to work on or to extend this new collection that forms the third part of a palindromic prime TRILOGY (SUPP  PWP  PDP). 
January 20, 2003 
Alex Kruppa & Paul Leyland
completed two more stages of the search for HP49. They successfully factored HP49(95).c153 into p68 * p85 after months of work. Method description & prime factors can be found at
Home Primes (update) I'm still wondering if they may have to go beyond 100 steps... 
January 14, 2003 
1.241 trillion digits of computed by Prof. Y. Kanada. WONplate 40 (update) 
January 2, 2003 
Jeff Heleen and Daniel Heuer each found new Palindromic Wing Primes (or PWP's for short)
Jeff prime proved a 4769digit PWP using Primo. (3)_{2384}1(3)_{2384} or (10^{4769}1)/3  2*10^{2384} while
Daniel got a worldrecord 95019digit PWP (9)_{47509}8(9)_{47509} or (10^{95019}1)  10^{47509} using PrimeForm.
The (palindromic) wings are really taking off... 