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 A096603 #4 Mar 30 2012 18:50:44 %S A096603 1,2,4,5,8,9,11,13,16,17,19,21,23,25,27,29,32,33,35,37,39,41,43,45,47, %T A096603 49,51,53,55,57,59,61,64,65,67,69,71,73,75,77,79,81,83,85,87,89,91,93, %U A096603 95,97,99,101,103,105,107,109,111,113,115,117,119,121,123,125,128,129 %N A096603 Numbers occurring twice in A096607. %C A096603 a(n) occurs more than twice in A096605; %C A096603 complement of A096604, a and A096604 are disjoint; %C A096603 A096602(a(n)) = A096604(n). %K A096603 nonn %O A096603 1,2 %A A096603 _Reinhard Zumkeller_, Jun 30 2004