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 A095863 #3 Mar 30 2012 17:29:16 %S A095863 3,13,44,140,446,1413,4471,14141,44720,141420,447213,1414213,4472135, %T A095863 14142135,44721359,141421355,447213594,1414213561,4472135954, %U A095863 14142135623,44721359549,141421356236,447213595499,1414213562372 %N A095863 Index of largest triangular number with n digits. %C A095863 Partial sums of A068094. %F A095863 a(n) = A068092(n+1) - 1. %Y A095863 Cf. A068092, A068093, A068094, A095864, A095865, A095866. %K A095863 base,easy,nonn %O A095863 1,1 %A A095863 _Ray Chandler_, Jun 28 2004