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 A303844 #8 May 03 2018 14:18:59 %S A303844 1,0,1,1,4,7,26,69,246,818,2976,10791,40591,153959,594753,2320696, %T A303844 9159498,36467012,146411208,592046830,2409946566,9867745442, %U A303844 40623068380,168058068487,698400767839,2914407151002,12208398647345,51322369218674,216463504458521 %N A303844 Number of noncrossing path sets on n nodes up to rotation with each path having at least two nodes. %H A303844 Andrew Howroyd, <a href="/A303844/b303844.txt">Table of n, a(n) for n = 0..200</a> %e A303844 Case n=4: There are 4 possibilities: %e A303844 . %e A303844 o---o o o o---o o---o %e A303844 | | / \ %e A303844 o---o o---o o---o o---o %e A303844 . %o A303844 (PARI) \\ See A303732 for NCPathSetsModCyclic %o A303844 Vec(NCPathSetsModCyclic(vector(30, k, k>1))) %Y A303844 Cf. A303730, A303732, A303836, A303839. %K A303844 nonn %O A303844 0,5 %A A303844 _Andrew Howroyd_, May 01 2018