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 A026357 #4 Mar 30 2012 18:56:06 %S A026357 0,5,10,20,33,43,61,74,97,123,141,172,206,229,268,294,338,385,416,468, %T A026357 502,559,619,658,723,791,835,908,955,1033,1114,1166,1252,1341,1398, %U A026357 1492,1552,1651,1753,1818,1925,1993,2105,2220,2293 %N A026357 a(n) = sum of the numbers between the two n's in A026354. %K A026357 nonn %O A026357 3,2 %A A026357 _Clark Kimberling_