A023260 Primes that remain prime through 2 iterations of function f(x) = 8x + 1.

2, 17, 101, 107, 401, 821, 947, 1151, 1487, 2027, 2207, 2411, 2741, 2927, 3851, 4391, 4691, 5231, 5861, 6701, 7001, 8297, 8807, 9341, 9587, 9851, 10067, 11117, 11447, 11897, 12107, 12911, 16187, 17657, 20681, 20771, 20807, 21221, 21227, 21491, 21521

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Primes p such that 8*p+1 and 64*p+9 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

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

Programs

Magma

[n: n in [1..100000] | IsPrime(n) and IsPrime(8*n+1) and IsPrime(64*n+9)] // Vincenzo Librandi, Aug 04 2010

Mathematica

Select[Prime[Range[2500]],And@@PrimeQ[Rest[NestList[8#+1&,#,2]]]&] (* Harvey P. Dale, Jan 26 2013 *)