A023250 Primes that remain prime through 2 iterations of function f(x) = 4x + 3.

2, 7, 11, 37, 67, 89, 109, 149, 179, 257, 439, 467, 571, 677, 691, 719, 929, 977, 1019, 1279, 1381, 1447, 1549, 1567, 1747, 1787, 1901, 1931, 2111, 2161, 2207, 2287, 2347, 2377, 2459, 2539, 2671, 2711, 2819, 3119, 3229, 3371, 3491, 3607, 3637, 3821, 3877

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Primes p such that 4*p+3 and 16*p+15 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

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

Crossrefs

Subsequence of A095278.

Programs

Magma

[n: n in [0..100000] | IsPrime(n) and IsPrime(4*n+3) and IsPrime(16*n+15)]; // Vincenzo Librandi, Aug 04 2010

Maple

A023250:=n->`if`(isprime(n) and isprime(4*n+3) and isprime(16*n+15), n, NULL): seq(A023250(n), n=1..10^4); # Wesley Ivan Hurt, Feb 12 2017

Mathematica

Select[Range@ 3900, Times @@ Boole@ PrimeQ@ NestList[4 # + 3 &, #, 2] > 0 &] (* Michael De Vlieger, Sep 13 2016 *)