cp's OEIS Frontend

A269786 Primes p such that 2*p + 31 is a square.

%I A269786 #23 Sep 08 2022 08:46:16
%S A269786 97,349,997,1609,2797,3769,6829,7549,10789,11689,13597,15649,16729,
%T A269786 22669,28069,32497,40597,44089,49597,59497,63709,70297,74869,86929,
%U A269786 89449,94597,113749,122497,128509,144169,147409,153997,164149,181789,196549,200329,207997
%N A269786 Primes p such that 2*p + 31 is a square.
%C A269786 Primes of the form 2*k^2 + 2*k - 15.
%t A269786 Select[Prime[Range[25000]], IntegerQ[Sqrt[2 # + 31]] &]
%o A269786 (Magma) [p: p in PrimesUpTo(300000) | IsSquare(2*p+31)];
%o A269786 (PARI) lista(nn) = forprime(p=2, nn, if (issquare(2*p+31), print1(p, ", "))); \\ _Michel Marcus_, Mar 22 2016
%o A269786 (Python)
%o A269786 from gmpy2 import is_prime,is_square
%o A269786 for p in range(3,10**6,2):
%o A269786     if(not is_square(2*p+31)):continue
%o A269786     elif(is_prime(p)):print(p)
%o A269786 # _Soumil Mandal_, Apr 07 2016
%Y A269786 Cf. A000040.
%Y A269786 Subsequence of A061241, A142108.
%Y A269786 Cf. similar sequences listed in A269784.
%K A269786 nonn
%O A269786 1,1
%A A269786 _Vincenzo Librandi_, Mar 22 2016