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 A046726 #29 Jul 15 2019 04:58:52 %S A046726 1,1,1,1,2,2,1,3,6,4,1,4,11,16,10,1,5,17,37,48,24,1,6,24,66,126,140, %T A046726 66,1,7,32,104,254,430,428,174,1,8,41,152,438,956,1454,1308,504,1,9, %U A046726 51,211,690,1796,3584,4976,4072,1406,1,10,62,282,1023,3028,7238,13256,16880,12796,4210 %N A046726 Triangle of numbers of semi-meanders of order n with k components. %C A046726 Rows are in order of decreasing number of components. Diagonals give number of semi-meanders with k components. - _Andrew Howroyd_, Nov 27 2015 %H A046726 Andrew Howroyd, <a href="/A046726/b046726.txt">Table of n, a(n) for n = 1..820</a> %H A046726 P. Di Francesco, O. Golinelli, and E. Guitter, <a href="https://arxiv.org/abs/hep-th/9506030">Meander, folding and arch statistics</a>, arXiv:hep-th/9506030, 1995. %H A046726 P. Di Francesco, O. Golinelli, and E. Guitter, <a href="https://doi.org/10.1016/S0895-7177(97)00202-1">Meander, folding and arch statistics</a>, Mathematical and Computer Modelling 26 (1997), 97-147. %e A046726 Triangle starts: %e A046726 1; %e A046726 1, 1; %e A046726 1, 2, 2; %e A046726 1, 3, 6, 4; %e A046726 1, 4, 11, 16, 10; %e A046726 1, 5, 17, 37, 48, 24; %e A046726 1, 6, 24, 66, 126, 140, 66; %e A046726 1, 7, 32, 104, 254, 430, 428, 174; %e A046726 1, 8, 41, 152, 438, 956, 1454, 1308, 504; %e A046726 ... %Y A046726 Diagonals include A000682, A046721, A046722, A046723, A046724, A046725. Columns include A000027, A046691. Row sums are in A000108 (Catalan numbers). %K A046726 nonn,tabl %O A046726 1,5 %A A046726 _N. J. A. Sloane_ %E A046726 More terms from Larry Reeves (larryr(AT)acm.org), Apr 05 2000 %E A046726 T(12,k)-T(40,k) from _Andrew Howroyd_, Dec 07 2015