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 A058194 #11 Feb 09 2020 14:26:02
%S A058194 1,3,21,162,1636,19977,298416,5300296,110219750,2639842989,
%T A058194 71859429837,2198244062193,74860247277672,2815351714711122,
%U A058194 116130005180284423,5222901881792429337,254791333526874348652,13420798291405599027605,760201936044714899316798,46137860613934391781325337,2990483661567310913388458734
%N A058194 Number of n-rowed matrices with entries {0,1,2,3} and all row sums 3, up to row and column permutation.
%o A058194 (PARI) \\ See A318951 for RowSumMats
%o A058194 a(n)=RowSumMats(n, 3*n, 3); \\ _Andrew Howroyd_, Sep 06 2018
%Y A058194 Row n=3 of A331485.
%Y A058194 Cf. A007717, A058407, A058409, A050913.
%K A058194 nonn
%O A058194 0,2
%A A058194 _Vladeta Jovovic_, Nov 27 2000
%E A058194 a(11)-a(20) from _Andrew Howroyd_, Sep 06 2018