World!OfNumbers |
WON plate 188 | |
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How many different primes divide all the ninedigitals ?
What is the largest prime factor in each case ?
What prime factor(s) has the least frequency of appearing ?
How many palindromic prime factors are there in each case ?
List of smallest and largest nine-/pandigital 9*semiprimes ?
To start with I give the smallest and largest nine- and pandigital
123456789 = 3
987654321 = 3
yielding already this subset {... ,3,...,17,...,3607,...,3803,...,379721,... }
and
1023456789 = 3
9876543210 = 2 x 3
yielding already this subset {2,3,5,...,17,...,2221,...,5689,...,379721,... } The rest is up to you. Good luck.
Some related sources
A178775 Smallest prime factors of zerofull restricted pandigital numbers.
A216203 Smallest prime that does not divide at least one n-digit zeroless pandigital number. | |||

A000188 Prime Curios! Prime Puzzle Wikipedia 188 Le nombre 188 |

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