A271667 - OEIS

%I #19 Sep 08 2022 08:46:16

%S 3,5,13,41,43,61,71,73,103,113,181,223,241,269,271,283,379,433,479,

%T 491,521,523,593,619,631,659,719,839,929,941,1009,1039,1069,1193,1249,

%U 1289,1319,1429,1433,1471,1489,1511,1553,1601,1613,1693,1699,1723,1753,1861

%N Primes p such that 6*p^2+6*p-1 is prime.

%H Vincenzo Librandi, <a href="/A271667/b271667.txt">Table of n, a(n) for n = 1..1000</a>

%e 3 is a term because 3 is prime and 6*3^2+6*3-1 is 71 which is prime. 13 is a term because 13 is prime and 6*13^2+6*13-1 is 1091 which is prime. - _Soumil Mandal_, Apr 14 2016

%t Select[Prime[Range[300]], PrimeQ[6 #^2 + 6 # - 1] &]

%o (Magma) [p: p in PrimesUpTo(2000) | IsPrime(6*p^2+6*p-1)];

%o (PARI) lista(nn) = forprime(p=2, nn, if(isprime(6*p^2+6*p-1), print1(p, ", "))); \\ _Altug Alkan_, Apr 12 2016

%o (Python)

%o from gmpy2 import is_prime

%o for p in range(3,10**5,2):

%o     if(not is_prime(p)):continue

%o     elif(is_prime(6*p**2+6*p-1)):print(p)

%o # _Soumil Mandal_, Apr 14 2016

%Y Cf. A171139, A171831, A171832, A261810, A271666.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Apr 12 2016