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 A026291 #5 Jan 06 2024 21:42:44 %S A026291 2,14,79,446,2530,14442,82913,478384,2771900,16119808,94038087, %T A026291 550083340,3225409094,18951732050,111562247565,657813211278, %U A026291 3884461464740,22968812720476,135978792939818 %N A026291 a(n) = T(2n-1,n), where T is the array in A026268. %Y A026291 Cf. A026268. %K A026291 nonn %O A026291 2,1 %A A026291 _Clark Kimberling_