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 A172931 #8 Apr 18 2020 22:26:08 %S A172931 1,393,248137,200148649,187403959401,193953937375521, %T A172931 215717608046511873,253310893747894263177,310323674631037864285609, %U A172931 393277602707575435993011793,512421117125922437799936404913 %N A172931 Number of n X 7 0..7 arrays with row sums 7 and column sums n. %H A172931 R. H. Hardin, <a href="/A172931/b172931.txt">Table of n, a(n) for n=1..45</a> %Y A172931 Column k=7 of A333901. %K A172931 nonn %O A172931 1,2 %A A172931 _R. H. Hardin_, Feb 06 2010