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 A067221 #12 Oct 14 2024 10:56:08 %S A067221 1,14,196,162722,21592075596,428134536074377254, %T A067221 1326740266296956878519910950 %N A067221 Number of n X n 0..13 matrices with all row and column sums equal. %Y A067221 Column k=13 of A202784. %K A067221 nonn,more %O A067221 0,2 %A A067221 _R. H. Hardin_, Feb 20 2002 %E A067221 a(5)-a(6) from _Sean A. Irvine_, Dec 10 2023 %E A067221 a(0)=1 prepended by _Andrew Howroyd_, Oct 14 2024