Search: id:A081425 Results 1-1 of 1 results found. %I A081425 %S A081425 719,1319,1699,2447,3343,4079,4139,4457,4517,4679,4703,5273,5647,6653, %T A081425 6793,7523,7529,7559,8599,9227,9587,9623,9839,10159,10343,10723,10771, %U A081425 11069,11213,11279,11321,11489,11863,11887,12163,12917,12919,13163 %N A081425 Class 6- primes. %D A081425 R. K. Guy, Unsolved Problems in Number Theory, A18. %H A081425 R. J. Mathar, Table of n, a(n) for n = 1..20000 %t A081425 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[1700], ClassMinusNbr[ Prime[ # ]] == 6 &]] %Y A081425 Cf. A005113, A056637, A005109, A005110, A005111, A005112, A081424, A081426, A081427, A081428, A081429, A081430. %Y A081425 Sequence in context: A151631 A034587 A111416 this_sequence A101797 A144767 A127227 %Y A081425 Adjacent sequences: A081422 A081423 A081424 this_sequence A081426 A081427 A081428 %K A081425 nonn %O A081425 1,1 %A A081425 Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 20 2003 Search completed in 0.001 seconds