OFFSET
1,1
COMMENTS
Primes of the form 2*k^2 + 2*k - 23.
FORMULA
a(1) = 17 because 2*17 + 47 = 81, which is a square.
MATHEMATICA
Select[Prime[Range[2500]], IntegerQ[Sqrt[2 # + 47]] &]
PROG
(Magma) [p: p in PrimesUpTo(50000) | IsSquare(2*p+47)];
(PARI) lista(nn) = {forprime(p=2, nn, if(issquare(2*p + 47), print1(p, ", "))); } \\ Altug Alkan, Mar 24 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, Mar 24 2016
STATUS
approved