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 A323973 #5 Feb 09 2019 20:53:43
%S A323973 1,28,406,4631,38304,249814,1357051,6362806,26400811,98755951,
%T A323973 337852708,1069253171,3159851197,8786784471,23140533785,58032604728,
%U A323973 139238130793,320911139366,712976624945,1531659348507,3190199728577,6457722870812,12731177730290,24491108899982
%N A323973 Number of 9 X n integer matrices (m_{i,j}) such that m_{1,1}=0, m_{9,n}=2, and all rows, columns, and falling diagonals are (weakly) monotonic without jumps of 2.
%H A323973 Alois P. Heinz, <a href="/A323973/b323973.txt">Table of n, a(n) for n = 0..10000</a>
%Y A323973 Row (or column) 9 of array in A323846.
%K A323973 nonn,easy
%O A323973 0,2
%A A323973 _Alois P. Heinz_, Feb 09 2019