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 A172048 #11 Sep 17 2017 22:34:38
%S A172048 2,14,23,32,38,41,50,53,59,68,74,77,83,86,95,98,104,113,116,122,128,
%T A172048 131,137,140,143,149,158,167,173,176,179,182,185,188,194,200,203,212,
%U A172048 215,218,221,230,233,239,242,248,254,257,263,266,275,278,281,284,293
%N A172048 a(n) = A104275(n) + A014076(n).
%C A172048 Alternatively: the sequence of the numbers 3*k-1 for all nonprime 2*k-1, k >= 1.
%H A172048 G. C. Greubel, <a href="/A172048/b172048.txt">Table of n, a(n) for n = 1..5000</a>
%t A172048 Flatten[Table[If[PrimeQ[2*n - 1], {}, 3*n - 1], {n, 1, 100}]]
%Y A172048 Cf. A104275, A014076.
%K A172048 nonn,easy,less
%O A172048 1,1
%A A172048 _Roger L. Bagula_, Jan 24 2010
%E A172048 The two equivalent definitions separated by the Assoc. Editors of the OEIS, Feb 02 2010