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 A072738 #2 May 01 2014 02:47:42 %S A072738 0,1,1,2,2,0,2,3,3,1,3,4,4,2,0,3,4,5,5,3,1,4,5,6,6,4,2,0,4,5,6,7,7,5, %T A072738 3,1,5,6,7,8,8,6,4,2,0,5,6,7,8,9,9,7,5,3,1,6,7,8,9,10,10,8,6,4,2,0,6, %U A072738 7,8,9,10,11,11,9,7,5,3,1,7,8,9,10,11,12,12,10,8,6,4,2,0,7,8,9,10,11,12,13 %N A072738 X-projection of the tabular N X N -> N bijection A072733. %o A072738 (Scheme) (define (A072738 n) (A025581 (A072732 n))) %Y A072738 The Y-projection is A072739. Composition of A025581 & A072732. A072785(n) = A072781(n)-A072738(n). %K A072738 nonn,tabl %O A072738 0,4 %A A072738 _Antti Karttunen_, Jun 12 2002