%I A081427
%S A081427 2879,20147,25903,34537,46049,58733,63317,65267,69029,69073,74759,80537,
%T A081427 86291,86341,103549,106487,108413,112877,120877,131687,135859,138053,
%U A081427 140939,141023,147647,155413,157427,165527,172681,187163,189949,207079
%N A081427 Class 8- primes.
%D A081427 R. K. Guy, Unsolved Problems in Number Theory, A18.
%H A081427 R. J. Mathar, <a href="b081427.txt">Table of n, a(n) for n = 1..20000</
               a>
%t A081427 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]]; ClassMinusNbr[n_] := Length[NestWhileList[f, n, UnsameQ, All]] 
               - 3; Prime[ Select[ Range[20000], ClassMinusNbr[ Prime[ # ]] == 8 
               &]]
%Y A081427 Cf. A005113, A056637, A005109, A005110, A005111, A005112, A081424, A081425, 
               A081426, A081428, A081429, A081430.
%Y A081427 Sequence in context: A020429 A067703 A125000 this_sequence A101999 A066174 
               A134856
%Y A081427 Adjacent sequences: A081424 A081425 A081426 this_sequence A081428 A081429 
               A081430
%K A081427 nonn
%O A081427 1,1
%A A081427 Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 20 2003