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%I #9 Jan 13 2014 11:58:07
%S 1021,1321,1381,1459,1877,2467,2503,2657,2707,3253,3313,3547,3701,
%T 3733,3907,4561,4817,4937,5441,5443,5527,5693,5839,5861,6037,6131,
%U 6211,6217,6277,6361,6373,6569,6653,7057,7243,7591,7753,7817,7883,8101,8123,8221
%N Class 5+ primes (for definition see A005105).
%D R. K. Guy, Unsolved Problems in Number Theory, A18.
%H T. D. Noe, <a href="/A081633/b081633.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[1040], ClassPlusNbr[ Prime[ # ]] == 5 &]]
%Y Cf. A005113, A005105, A005106, A005107, A005108, A081634, A081635, A081636, A081637, A081638, A081639.
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Mar 20 2003
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