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 A194109 #5 Mar 30 2012 18:57:40 %S A194109 1,3,6,2,5,9,10,15,4,8,13,14,20,21,7,12,18,19,26,27,28,36,11,17,24,25, %T A194109 33,34,35,44,45,55,16,23,31,32,41,42,43,53,54,65,66,78,22,30,39,40,50, %U A194109 51,52,63,64,76,77,90,91,29,38,48,49,60,61,62,74,75,88,89,103 %N A194109 Inverse permutation of A194108; every positive integer occurs exactly once. %t A194109 (See A194108.) %Y A194109 Cf. A194108. %K A194109 nonn %O A194109 1,2 %A A194109 _Clark Kimberling_, Aug 15 2011