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 A054938 #15 May 16 2018 08:28:29 %S A054938 0,0,0,1,26,348,4466,61726,949795,16331482,312298796,6587217199, %T A054938 152030203190,3811719561156,103171205826822,2998417379370294, %U A054938 93127344062857976,3078376281077418971,107905190923235526392 %N A054938 Number of chiral chord diagrams on n nodes. %H A054938 V. A. Liskovets, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL3/LISK/Derseq.html">Some easily derivable sequences</a>, J. Integer Sequences, 3 (2000), #00.2.2. %F A054938 a(n) = A054499(n)-A018191(n). [Liskovets, referring to offset 1 in A054499]. - _R. J. Mathar_, Oct 01 2011 %K A054938 nonn,easy %O A054938 1,5 %A A054938 _N. J. A. Sloane_, May 24 2000