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 A303869 #9 May 03 2018 14:38:42 %S A303869 1,1,1,1,1,1,3,4,2,1,4,11,8,2,1,10,34,39,16,3,1,16,92,144,90,25,3,1, %T A303869 36,256,545,473,197,40,4,1,64,672,1878,2184,1246,370,56,4,1,136,1762, %U A303869 6296,9436,7130,2910,658,80,5,1,256,4480,20100,38025,36690,19698,6090,1080,105,5,1 %N A303869 Triangle read by rows: T(n,k) = number of noncrossing path sets on n nodes up to rotation with k paths and isolated vertices allowed. %H A303869 Andrew Howroyd, <a href="/A303869/b303869.txt">Table of n, a(n) for n = 1..1275</a> %e A303869 Triangle begins: %e A303869 1; %e A303869 1, 1; %e A303869 1, 1, 1; %e A303869 3, 4, 2, 1; %e A303869 4, 11, 8, 2, 1; %e A303869 10, 34, 39, 16, 3, 1; %e A303869 16, 92, 144, 90, 25, 3, 1; %e A303869 36, 256, 545, 473, 197, 40, 4, 1; %e A303869 64, 672, 1878, 2184, 1246, 370, 56, 4, 1; %e A303869 136, 1762, 6296, 9436, 7130, 2910, 658, 80, 5, 1; %e A303869 ... %o A303869 (PARI) \\ See A303732 for NCPathSetsModCyclic %o A303869 { my(rows=Vec(NCPathSetsModCyclic(vector(10, k, y))-1)); %o A303869 for(n=1, #rows, for(k=1,n,print1(polcoeff(rows[n],k), ", ")); print;)} %Y A303869 Row sums are A303836. %Y A303869 Column 1 is A051437(n-3). %Y A303869 Cf. A303844, A303732, A303864, A303868. %K A303869 nonn,tabl %O A303869 1,7 %A A303869 _Andrew Howroyd_, May 01 2018