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 A223096 #32 Feb 02 2018 03:24:12 %S A223096 1,1,2,5,13,36,102,299,889,2698,8267,25684,80349,253872,806334, %T A223096 2580279,8290645,26794566,86881179,283034120,924521718,3031535538, %U A223096 9962795554 %N A223096 Number of symmetric meander shapes with 2n+1 crossings. %C A223096 Number of symmetric foldings of 2n+1 stamps (A007822) in which end leaves are outwards. [_Stéphane Legendre_, Apr 09 2013] %H A223096 Stéphane Legendre, <a href="/A223096/a223096.pdf">Illustration of initial terms</a> %H A223096 S. Legendre, <a href="http://arxiv.org/abs/1302.2025">Foldings and Meanders</a>, arXiv preprint arXiv:1302.2025 [math.CO], 2013. %H A223096 S. Legendre, <a href="http://ajc.maths.uq.edu.au/pdf/58/ajc_v58_p275.pdf">Foldings and Meanders</a>, Aust. J. Comb. 58(2), 275-291, 2014. %H A223096 <a href="/index/Fo#fold">Index entries for sequences obtained by enumerating foldings</a> %Y A223096 Cf. A007822, A077055. %K A223096 nonn,more %O A223096 0,3 %A A223096 _N. J. A. Sloane_, Mar 30 2013