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 A058390 #13 Sep 15 2019 04:07:06 %S A058390 1,5,53,458,3411,19865,95214,383714,1346183,4202086,11905966,31061806, %T A058390 75533056,172800689,374861365,775978710,1541027694,2949003213, %U A058390 5458806804,9805626744,17140511056 %N A058390 Number of 4 X 4 matrices with nonnegative integer entries and all row sums equal to n, up to row and column permutation. %H A058390 Andrew Howroyd, <a href="/A058390/b058390.txt">Table of n, a(n) for n = 0..1000</a> %H A058390 Vladeta Jovovic, <a href="/A058389/a058389a.pdf">Number of m x m nonnegative integer matrices with all row sums equal to n, up to row and column permutation.</a> %t A058390 (* See A318951 for RowSumMats *) %t A058390 a[n_] := RowSumMats[4, 4, n]; %t A058390 a /@ Range[0, 20] (* _Jean-François Alcover_, Sep 15 2019, after _Andrew Howroyd_ *) %o A058390 (PARI) \\ See A318951 for RowSumMats %o A058390 a(n)=RowSumMats(4, 4, n); \\ _Andrew Howroyd_, Sep 05 2018 %Y A058390 Row 4 of A318951. %Y A058390 Cf. A002620, A058389, A058391, A058392, A001496, A052280, A052281. %K A058390 nonn %O A058390 0,2 %A A058390 _Vladeta Jovovic_, Nov 24 2000