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%I #29 Sep 08 2022 08:44:47
%S 2,17,47,61,101,131,151,331,367,461,607,751,937,971,1151,1321,1327,
%T 1361,1481,1511,1607,1811,1847,1907,2081,2287,2347,2357,2791,2851,
%U 2971,3251,3257,3457,3491,3581,3761,4007,4091,4127,4861,4967,5231,5347,5387,5407
%N Primes that remain prime through 2 iterations of function f(x) = 6x + 1.
%C Primes p such that 6*p+1 and 36*p+7 are also primes. - _Vincenzo Librandi_, Aug 04 2010
%C Subsequence of A007693. - _Michel Marcus_, Oct 17 2015
%H John Cerkan, <a href="/A023256/b023256.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) == 1 or 7 (mod 10) for n > 1. - _John Cerkan_, Sep 14 2016
%t Select[Prime[Range[800]],AllTrue[Rest[NestList[6#+1&,#,2]],PrimeQ]&] (* _Harvey P. Dale_, Oct 17 2020 *)
%o (Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(6*n+1) and IsPrime(36*n+7)] // _Vincenzo Librandi_, Aug 04 2010
%o (PARI) lista(nn) = forprime(n=1, nn, if (isprime(p=6*n+1) && isprime(6*p+1), print1(n, ", "))); \\ _Michel Marcus_, Oct 17 2015
%Y Cf. A007693.
%K nonn
%O 1,1
%A _David W. Wilson_
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