This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A081425 #8 Sep 22 2012 11:26:56
%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 (for definition see A005109).
%D A081425 R. K. Guy, Unsolved Problems in Number Theory, A18.
%H A081425 R. J. Mathar, <a href="/A081425/b081425.txt">Table of n, a(n) for n = 1..20000</a>
%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.
%K A081425 nonn
%O A081425 1,1
%A A081425 _Robert G. Wilson v_, Mar 20 2003