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%I #4 Mar 31 2012 10:22:32
%S 2,3,4,5,6,7,8,10,11,13,14,15,16,17,18,19,20,21,22,28,30,31,33,34,35,
%T 37,38,39,40,42,44,45,47,51,52,53,55,56,58,59,61,64,65,66,69,72,76,79,
%U 81,82,84,86,87,91,95,98,100,102,103,104,105,107,108,109,113,115,116,118
%N Numbers n such that 3*n^2 + 5*n +1 is either a prime or a power of three multiplied with a prime.
%e 3*2^2 + 5*2 + 1 = 23, which is prime. Therefore 2 is in the sequence.
%e 3*4^2 + 5*4 + 1 = 3*23, a prime multiplied by a power of 3. Hence 3 is in the sequence.
%t a = {}; For[n = 1, n < 130, n++, m = 3*n^2 + 5*n + 1; If[PrimeQ[m], AppendTo[a, n]]; While[IntegerQ[m/3], m = m/3]; If[PrimeQ[m], AppendTo[a, n]]]; Union[a, a]
%K nonn,less
%O 1,1
%A _J. M. Bergot_, Aug 27 2007
%E Edited, corrected and extended by _Stefan Steinerberger_, Aug 29 2007
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