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 A333397 #15 Mar 23 2020 21:10:05 %S A333397 1,1,1,1,0,0,1,1,1,0,1,0,1,0,0,1,1,2,1,0,0,1,0,2,0,1,0,0,1,1,3,4,5,1, %T A333397 0,0,1,0,3,0,10,0,1,0,0,1,1,4,9,26,28,17,1,0,0,1,0,4,0,47,0,97,0,1,0, %U A333397 0,1,1,5,17,91,291,639,359,71,1,0,0,1,0,5,0,149,0,2789,0,1635,0,1,0,0 %N A333397 Array read by antidiagonals: T(n,k) is the number of connected k-regular multigraphs on n unlabeled nodes, loops allowed, n >= 0, k >= 0. %C A333397 This sequence can be derived from A167625 by inverse Euler transform. %H A333397 Andrew Howroyd, <a href="/A333397/b333397.txt">Table of n, a(n) for n = 0..405</a> (first 28 antidiagonals) %F A333397 Column k is the inverse Euler transform of column k of A167625. %e A333397 Array begins: %e A333397 ========================================================= %e A333397 n\k | 0 1 2 3 4 5 6 7 8 %e A333397 ----+---------------------------------------------------- %e A333397 0 | 1 1 1 1 1 1 1 1 1 ... %e A333397 1 | 1 0 1 0 1 0 1 0 1 ... %e A333397 2 | 0 1 1 2 2 3 3 4 4 ... %e A333397 3 | 0 0 1 0 4 0 9 0 17 ... %e A333397 4 | 0 0 1 5 10 26 47 91 149 ... %e A333397 5 | 0 0 1 0 28 0 291 0 1934 ... %e A333397 6 | 0 0 1 17 97 639 2789 12398 44821 ... %e A333397 7 | 0 0 1 0 359 0 35646 0 1631629 ... %e A333397 8 | 0 0 1 71 1635 40264 622457 8530044 89057367 ... %e A333397 9 | 0 0 1 0 8296 0 14019433 0 6849428873 ... %e A333397 ... %Y A333397 Columns k=3..8 (with interspersed 0's for odd k) are: A005967, A085549, A129430, A129432, A129434, A129436. %Y A333397 Cf. A167625 (not necessarily connected), A322115 (not necessarily regular), A328682 (loopless), A333330. %K A333397 nonn,tabl %O A333397 0,18 %A A333397 _Andrew Howroyd_, Mar 18 2020