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 A290688 #13 Oct 20 2017 17:18:52 %S A290688 1,2,26,854,52938,5317342,788783482,162272284974,44237669097482, %T A290688 15439822086531614,6715538352190953498,3561963935537880874894, %U A290688 2263250481436117389497386,1697243825672918269588268286,1483337827671250048404238399034,1494549066141865576239455292770414 %N A290688 Number of linear chord diagrams having 2n chords and minimal chord length n. %F A290688 a(n) = A293881(2n,n). %Y A290688 Cf. A293881. %K A290688 nonn %O A290688 0,2 %A A290688 _Alois P. Heinz_, Oct 18 2017