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 A026271 #4 Mar 30 2012 18:56:05 %S A026271 0,3,6,14,25,33,49,60,81,105,121,150,182,203,240,264,306,351,380,430, %T A026271 462,517,575,612,675,741,783,854,899,975,1054,1104,1188,1275,1330, %U A026271 1422,1480,1577,1677,1740,1845,1911,2021,2134,2205 %N A026271 a(n) = sum of the numbers between the two n's in A026242. %K A026271 nonn %O A026271 1,2 %A A026271 _Clark Kimberling_