Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #4 Mar 30 2012 17:34:20
%S 3,17,47,107,173,269,503,641,809,983,1187,1637,2441,2753,4157,4547,
%T 4967,5393,5849,6311,6803,7829,8363,9497,11981,12653,13331,14753,
%U 15497,17027,22943,26723,29753,31859,32933,38609,39791,42221,47297,49943,58313
%N Primes of the form n^2+5n+c (n>=0), where c=3 for even n and c=-3 for odd n.
%C Alternating Euler quadratic prime generating polynomial.
%D Harvey Cohn, Advanced Number Theory,Dover, New York, 1962, page 155.
%t f[n_] := If[Mod[n, 2] == 1, n^2 + 5*n - 3, n^2 + 5*n + 3] b = Flatten[Table[If[PrimeQ[f[n]] == True, f[n], {}], {n, 1, 100}]]
%o (PARI) m=250;for(n=1,m,k=n^2+5*n+3-6*(n%2);if(isprime(k),print1(k,",")))
%Y Cf. A014209, A082605.
%K nonn
%O 1,1
%A _Roger L. Bagula_, Apr 16 2006
%E Edited and extended by _N. J. A. Sloane_, Apr 17 2006