2*(105-1)/9 + 5*104 + 5*102 + 5
```Using Pari/gp (< 1s)
gp > isprime(2*(10^5-1)/9+5*10^4+5*10^2+5)
%1 = 1

```

2*(1011-1)/9 + 5*1010 + 5*105 + 5
```Using Pari/gp (< 1s)
gp > isprime(2*(10^11-1)/9+5*10^10+5*10^5+5)
%1 = 1

```

2*(1017-1)/9 + 5*1016 + 5*108 + 5
```Using Pari/gp (< 1s)
gp > isprime(2*(10^17-1)/9+5*10^16+5*10^8+5)
%1 = 1

```

2*(1047-1)/9 + 5*1046 + 5*1023 + 5
```Using Pari/gp (< 1s)
gp > isprime(2*(10^47-1)/9+5*10^46+5*10^23+5)
%1 = 1

```

2*(1061-1)/9 + 5*1060 + 5*1030 + 5
```Using Pari/gp (< 1s)
gp > isprime(2*(10^61-1)/9+5*10^60+5*10^30+5)
%1 = 1

```

2*(10101-1)/9 + 5*10100 + 5*1050 + 5
```Using Pari/gp (< 1s)
gp > isprime(2*(10^101-1)/9+5*10^100+5*10^50+5)
%1 = 1

```

2*(10149-1)/9 + 5*10148 + 5*1074 + 5
```Using Pari/gp (< 1s)
gp > isprime(2*(10^149-1)/9+5*10^148+5*10^74+5)
%1 = 1

```

2*(10169-1)/9 + 5*10168 + 5*1084 + 5
```Using Pari/gp (< 1s)
gp > isprime(2*(10^169-1)/9+5*10^168+5*10^84+5)
%1 = 1

```

2*(10239-1)/9 + 5*10238 + 5*10119 + 5
```Using Pari/gp (< 1s)
gp > isprime(2*(10^239-1)/9+5*10^238+5*10^119+5)
%1 = 1

```

2*(10485-1)/9 + 5*10484 + 5*10242 + 5
```Using Pari/gp (time = 6,625 ms)
gp > default(parisizemax,"1G")
gp > isprime(2*(10^485-1)/9+5*10^484+5*10^242+5)
%1 = 1

```

```

```

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Patrick De Geest - Belgium - Short Bio - Some Pictures
E-mail address : pdg@worldofnumbers.com