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 A172643 #7 May 09 2020 21:24:24 %S A172643 1,212941,2320792657,141444270208645,8107975032968711941, %T A172643 641062514242765723819621,56688799539093817446748651801, %U A172643 5657362648396875453954444188314837 %N A172643 Number of n X 13 0..2 arrays with row sums 13 and column sums n. %H A172643 R. H. Hardin, <a href="/A172643/b172643.txt">Table of n, a(n) for n=1..16</a> %Y A172643 Column k=13 of A334549. %K A172643 nonn %O A172643 1,2 %A A172643 _R. H. Hardin_, Feb 06 2010