A023289 Primes that remain prime through 3 iterations of function f(x) = 6x + 7.

5, 37, 127, 347, 977, 2017, 3607, 5477, 9137, 10487, 13687, 14057, 14107, 19037, 19697, 19727, 20507, 22157, 23887, 24097, 25237, 25307, 26717, 26777, 27107, 29347, 30697, 33757, 33997, 34667, 34847, 35117, 35227, 37057, 40577, 40627, 41177, 41597

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Primes p such that 6*p+7, 36*p+49 and 216*p+301 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

• John Cerkan, Table of n, a(n) for n = 1..10000

Crossrefs

Subsequence of A023222, A023258, and A153218.

Programs

Magma

[n: n in [1..150000] | IsPrime(n) and IsPrime(6*n+7) and IsPrime(36*n+49) and IsPrime(216*n+301)] // Vincenzo Librandi, Aug 04 2010

Formula

a(n) == 7 (mod 10), for n > 1. - John Cerkan, Sep 21 2016