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%I #7 Jan 13 2014 12:00:56
%S 2917,4933,5413,7507,8167,8753,10567,10627,11047,11261,11677,12073,
%T 12251,12421,12433,12553,12721,14293,15017,17041,18181,18493,19267,
%U 19333,20023,21193,21313,21661,22397,24481,25933,26261,26437,27361
%N Class 6+ primes.
%D R. K. Guy, Unsolved Problems in Number Theory, A18.
%H T. D. Noe, <a href="/A081634/b081634.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[3000], ClassPlusNbr[ Prime[ # ]] == 6 &]]
%Y Cf. A005113, A005105, A005106, A005107, A005108, A081633, A081635, A081636, A081637, A081638, A081639.
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Mar 20 2003
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