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 A323967 #10 Feb 09 2019 18:53:11
%S A323967 1,1,4,25,94,266,632,1332,2570,4631,7900,12883,20230,30760,45488,
%T A323967 65654,92754,128573,175220,235165,311278,406870,525736,672200,851162,
%U A323967 1068147,1329356,1641719,2012950,2451604,2967136,3569962,4271522,5084345,6022116,7099745
%N A323967 Number of 3 X n integer matrices (m_{i,j}) such that m_{1,1}=0, m_{3,n}=2, and all rows, columns, and falling diagonals are (weakly) monotonic without jumps of 2.
%H A323967 Alois P. Heinz, <a href="/A323967/b323967.txt">Table of n, a(n) for n = 0..10000</a>
%H A323967 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (7,-21,35,-35,21,-7,1).
%F A323967 G.f.: -(x^7-5*x^6+7*x^5+3*x^4-17*x^3+18*x^2-6*x+1)/(x-1)^7.
%F A323967 a(n) = 2+((((((n+12)*n+55)*n+120)*n-236)*n-312)*n)/360 for n > 0, a(0) = 1.
%p A323967 a:= n-> `if`(n=0, 1, 2+((((((n+12)*n+55)*n+120)*n-236)*n-312)*n)/360):
%p A323967 seq(a(n), n=0..40);
%Y A323967 Row (or column) 3 of array in A323846.
%K A323967 nonn,easy
%O A323967 0,3
%A A323967 _Alois P. Heinz_, Feb 09 2019