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 A026880 #4 Mar 30 2012 18:56:11 %S A026880 1,1,3,4,12,17,50,73,212,315,909,1365,3931,5940,17122,25960,75053, %T A026880 113951,330917,502399,1467067,2224888,6537922,9896852,29281109, %U A026880 44218651,131765882,198432519,595663485,894311205,2704572795 %N A026880 a(n) = T(n,m) + T(n,m+1) + ... + T(n,n), m=[ (n+1)/2 ], T given by A026758. %K A026880 nonn %O A026880 1,3 %A A026880 _Clark Kimberling_