A124825 Numbers k such that 10k + 7 and 7k + 10 are primes.

1, 3, 9, 13, 27, 31, 33, 39, 57, 67, 79, 87, 93, 109, 111, 121, 159, 163, 169, 177, 187, 223, 229, 237, 241, 267, 277, 303, 351, 363, 367, 369, 379, 387, 421, 433, 439, 451, 463, 493, 507, 519, 523, 541, 571, 573, 589, 603, 621, 633, 639, 663, 673, 697, 699

Offset: 1

Author

Zak Seidov, Nov 09 2006

Keywords

• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Intersection of A102342 and A111250. - Michel Marcus, Jan 22 2018

Programs

Magma

[n: n in [0..700] | IsPrime(10*n+7) and IsPrime(7*n+10)] // Vincenzo Librandi, Mar 26 2010

Mathematica

Select[Range[700],AllTrue[{10#+7,7#+10},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Oct 05 2019 *)