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 A113782 #2 Mar 30 2012 17:27:47 %S A113782 1,3,2,6,5,10,15,4,21,9,28,36,8,45,14,55,20,66,78,7,91,27,105,120,13, %T A113782 136,35,153,44,171,190,12,210,54,231,253,19,276,65,300,325,26,351,77, %U A113782 378,90,406,435,11,465,104,496,528,34,561,119,595,135,630,666,18,703 %N A113782 a(n) = k such that A083087(k-1) = n. %C A113782 Sequence is a permutation of the positive integers; inverse permutation to sequence A083087 taken with offset 1. %e A113782 A083087(9) = 6, hence a(6) = 10. %Y A113782 Cf. A083087. %K A113782 nonn %O A113782 1,2 %A A113782 _Klaus Brockhaus_, Jan 19 2006