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 A026091 #5 Jun 23 2013 10:32:25 %S A026091 1,1,18,183,1927,20655,224498,2465815,27304863,304313548,3409370698, %T A026091 38362211823,433219457730,4907408334066,55737813431070, %U A026091 634528087334283,7238225267825429,82716464152842756,946771870186411896,10852263461880981957 %N A026091 a(n) = T(4n,n), where T is the array defined in A026082. %K A026091 nonn %O A026091 0,3 %A A026091 _Clark Kimberling_