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%I M5261 #19 Jan 13 2014 11:57:34
%S 37,103,113,151,157,163,173,181,193,227,233,257,277,311,331,337,347,
%T 353,379,389,397,401,409,421,457,463,467,487,491,521,523,541,547,569,
%U 571,601,607,613,631,653,683,701,727,733,773,787,797,811,821,829,853,857
%N Class 3+ primes (for definition see A005105).
%D R. K. Guy, Unsolved Problems in Number Theory, A18.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H T. D. Noe, <a href="/A005107/b005107.txt">Table of n, a(n) for n=1..10000</a>
%p For Maple program see Mathar link in A005105.
%t PrimeFactors[n_Integer] := Flatten[ Table[ #[[1]], {1}] & /@ FactorInteger[n]]; f[n_Integer] := Block[{m = n}, If[m == 0, m = 1, While[ IntegerQ[m/2], m /= 2]; While[ IntegerQ[m/3], m /= 3]]; Apply[Times, PrimeFactors[m] + 1]]; ClassPlusNbr[n_] := Length[ NestWhileList[f, n, UnsameQ, All]] - 3; Prime[ Select[ Range[150], ClassPlusNbr[ Prime[ # ]] == 3 &]]
%Y Cf. A005113, A005105, A005106, A005108.
%K nonn
%O 1,1
%A _N. J. A. Sloane_, _Simon Plouffe_
%E Edited and extended by _Robert G. Wilson v_, Mar 20 2003
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