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 A175857 #2 Mar 30 2012 19:00:24 %S A175857 1,2,3,4,5,6,7,10,11,12,13,16,17,18,19,20,21,22,23,26,27,28,29,30,31, %T A175857 34,35,36,37,40,41,42,43,44,45,46,47,48,49,50,51,52,53,56,57,58,59,60, %U A175857 61,64,65,66,67,68,69,70,71,72,73,76,77,78,79,80,81,82,83,84,85,86,87,88 %N A175857 a(n) = possible values of A175856(m) in increasing order, where A175856(m): a(m) = m for m = noncomposites, a(m) = previous term - 1 for m = composites. %C A175857 Complement of A175859(n). A175860(a(n)) = 1, A175862(a(n)) >= 1. %Y A175857 Cf. A175856, A175858, A175859, A175860, A175861, A175862. %K A175857 nonn %O A175857 1,2 %A A175857 _Jaroslav Krizek_, Sep 29 2010