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 A293963 #4 Oct 20 2017 17:03:36 %S A293963 1,1,10,300,18186,1838508,278873238,59240617044,16785089537034, %T A293963 6116748053227032,2787180218661133026,1552687010566633714620, %U A293963 1038232662085139704575042,820642288423711927490012112,756912885595843667978969686938,805677646550729982087279165847716 %N A293963 Number of linear chord diagrams having 2n chords and maximal chord length n, a(0)=1. %F A293963 a(n) = A293961(2n,n). %Y A293963 Cf. A293961. %K A293963 nonn %O A293963 0,3 %A A293963 _Alois P. Heinz_, Oct 20 2017