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 A162688 #4 Mar 31 2012 12:38:25
%S A162688 4,6,12,24,36,60,132
%N A162688 Strictly positive numbers n such that 12*n/(12+n) are integers.
%C A162688 The 12 row of A127730.
%C A162688 The ansatz 12*n/(12+n)=j (any integer j) yields n=12*j/(12-j) which demonstrates that the sequence is finite if n>=0. [R. J. Mathar, Jul 13 2009]
%t A162688 f[a_,b_]:=(a*b)/(a+b); a=12;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]],AppendTo[lst,n]],{n,9!}];lst
%Y A162688 Cf. A127730. [From _Franklin T. Adams-Watters_, Aug 07 2009]
%K A162688 nonn,fini,full
%O A162688 1,1
%A A162688 _Vladimir Joseph Stephan Orlovsky_, Jul 10 2009
%E A162688 Edited by _R. J. Mathar_, Jul 13 2009