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 A361241 #8 Mar 11 2023 00:13:35 %S A361241 1,1,1,6,35,349,3766,45632,580203,7687128,104898024,1466605630, %T A361241 20916933674,303368072539,4463328542008,66484512715040, %U A361241 1001084180891355,15217675702394661,233285495922344929,3603276856175739600,56033315904277236728,876698296980033411125 %N A361241 Number of nonequivalent noncrossing 4-gonal cacti with n polygons up to rotation and reflection. %H A361241 Andrew Howroyd, <a href="/A361241/b361241.txt">Table of n, a(n) for n = 0..500</a> %F A361241 a(2*n) = (A361238(2*n) + binomial(7*n + 1, n)/(7*n + 1))/2; a(2*n+1) = (A361238(2*n+1) + 4*binomial(7*n + 4, n)/(7*n + 4))/2. %Y A361241 Column 4 of A361239. %Y A361241 Cf. A361238. %K A361241 nonn %O A361241 0,4 %A A361241 _Andrew Howroyd_, Mar 06 2023