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%I #15 Aug 07 2024 11:00:48
%S 1,2,4,5,7,8,11,13,14,16,17,20,22,25,26,31,35,38,40,41,44,46,50,52,58,
%T 59,61,68,71,73,77,79,80,82,88,92,94,95,101,103,106,107,112,115,116,
%U 125,130,137,139,140,146,154,157,158,163,167,169,170,176,178,179,193,205
%N Numbers n such that 2*n^2 + 9 is prime.
%e If n=26 then (2*n^2) + 9 = 1361 (prime).
%p a:=proc(n) if isprime(2*n^2+9)=true then n else fi end: seq(a(n),n=0..280); # _Emeric Deutsch_, Oct 06 2005
%t Select[Range[205], PrimeQ[2#^2+9] &] (* _Stefano Spezia_, Aug 07 2024 *)
%o (PARI) is(n)=isprime(2*n^2+9) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y Cf. A339048.
%K nonn,easy
%O 1,2
%A _Parthasarathy Nambi_, Oct 05 2005
%E More terms from _Emeric Deutsch_, Oct 06 2005