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 A321760 #12 Jan 28 2024 18:10:42 %S A321760 1,0,0,0,1,1,7,9,37,79,273,755,2648,8432,29872,104624,384759,1432655, %T A321760 5502563,21533141,86291313,352654980,1471073073,6253397866, %U A321760 27083003687,119399628021,535591458635,2443030798539,11326169401988,53343974825122,255121588496338 %N A321760 Number of non-isomorphic multiset partitions of weight n with no constant parts or vertices that appear in only one part. %C A321760 Also the number of nonnegative integer matrices up to row and column permutations with sum of elements equal to n in which every row and column has at least two nonzero entries. %C A321760 The weight of a multiset partition is the sum of sizes of its parts. Weight is generally not the same as number of vertices. %H A321760 Andrew Howroyd, <a href="/A321760/b321760.txt">Table of n, a(n) for n = 0..50</a> %e A321760 Non-isomorphic representatives of the a(4) = 1 through a(7) = 9 multiset partitions: %e A321760 {{1,2},{1,2}} {{1,2},{1,2,2}} {{1,1,2},{1,2,2}} {{1,1,2},{1,2,2,2}} %e A321760 {{1,2},{1,1,2,2}} {{1,2},{1,1,2,2,2}} %e A321760 {{1,2},{1,2,2,2}} {{1,2},{1,2,2,2,2}} %e A321760 {{1,2,2},{1,2,2}} {{1,2,2},{1,1,2,2}} %e A321760 {{1,2,3},{1,2,3}} {{1,2,2},{1,2,2,2}} %e A321760 {{1,2},{1,2},{1,2}} {{1,2,3},{1,2,3,3}} %e A321760 {{1,2},{1,3},{2,3}} {{1,2},{1,2},{1,2,2}} %e A321760 {{1,2},{1,3},{2,3,3}} %e A321760 {{1,3},{2,3},{1,2,3}} %o A321760 (PARI) Vec(G(20,1)) \\ G defined in A369286. - _Andrew Howroyd_, Jan 28 2024 %Y A321760 Row sums of A369286. %Y A321760 Cf. A001970, A007716, A050535, A055884, A120733, A317533, A320665, A320798, A320801, A320808, A321407. %K A321760 nonn %O A321760 0,7 %A A321760 _Gus Wiseman_, Nov 29 2018 %E A321760 a(11) onwards from _Andrew Howroyd_, Jan 27 2024