# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a117012
Showing 1-1 of 1

%I A117012 #4 Mar 30 2012 17:34:20
%S A117012 3,17,47,107,173,269,503,641,809,983,1187,1637,2441,2753,4157,4547,
%T A117012 4967,5393,5849,6311,6803,7829,8363,9497,11981,12653,13331,14753,
%U A117012 15497,17027,22943,26723,29753,31859,32933,38609,39791,42221,47297,49943,58313
%N A117012 Primes of the form n^2+5n+c (n>=0), where c=3 for even n and c=-3 for odd n.
%C A117012 Alternating Euler quadratic prime generating polynomial.
%D A117012 Harvey Cohn, Advanced Number Theory,Dover, New York, 1962, page 155.
%t A117012 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 A117012 (PARI) m=250;for(n=1,m,k=n^2+5*n+3-6*(n%2);if(isprime(k),print1(k,",")))
%Y A117012 Cf. A014209, A082605.
%K A117012 nonn
%O A117012 1,1
%A A117012 _Roger L. Bagula_, Apr 16 2006
%E A117012 Edited and extended by _N. J. A. Sloane_, Apr 17 2006

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE