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 A005112 M5289 #18 Sep 22 2012 11:10:27
%S A005112 47,139,167,179,269,277,347,461,467,499,599,643,691,709,797,827,829,
%T A005112 839,857,863,967,997,1013,1019,1039,1063,1069,1151,1163,1181,1289,
%U A005112 1367,1381,1399,1427,1487,1493,1499,1579,1609,1619,1657,1867,1877,1889,1933,1979
%N A005112 Class 4- primes (for definition see A005109).
%D A005112 R. K. Guy, Unsolved Problems in Number Theory, A18.
%D A005112 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A005112 R. J. Mathar, <a href="/A005112/b005112.txt">Table of n, a(n) for n = 1..20000</a>
%t A005112 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[300], ClassMinusNbr[ Prime[ # ]] == 4 &]]
%Y A005112 Cf. A005113, A056637, A005109, A005110, A005111, A081424, A081425, A081426, A081427, A081428, A081429, A081430
%K A005112 nonn
%O A005112 1,1
%A A005112 _N. J. A. Sloane_, _Simon Plouffe_
%E A005112 Edited and extended by _Robert G. Wilson v_, Mar 20 2003