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 A250772 #8 Nov 19 2018 07:19:00 %S A250772 72,130,216,350,572,962,1680,3046,5700,10922,21272,41870,82956,165010, %T A250772 328992,656822,1312340,2623226,5244840,10487902,20973852,41945570, %U A250772 83888816,167775110,335547492,671092042,1342180920,2684358446,5368713260 %N A250772 Number of (4+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction. %H A250772 R. H. Hardin, <a href="/A250772/b250772.txt">Table of n, a(n) for n = 1..210</a> %F A250772 Empirical: a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4); a(n) = 20*2^(n-1) + 4*n^2 + 26*n + 22. %F A250772 Empirical g.f.: 2*x*(36 - 115*x + 107*x^2 - 32*x^3) / ((1 - x)^3*(1 - 2*x)). - _Colin Barker_, Nov 19 2018 %e A250772 Some solutions for n=4: %e A250772 ..1..1..0..1..0....0..0..0..0..0....0..0..0..0..0....1..1..0..0..0 %e A250772 ..1..1..0..1..1....0..0..0..0..0....1..1..1..1..1....1..1..0..0..0 %e A250772 ..1..1..0..1..1....0..0..0..0..0....0..0..0..0..0....1..1..1..1..1 %e A250772 ..1..1..0..1..1....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0 %e A250772 ..1..1..0..1..1....0..0..0..0..0....0..0..1..1..1....1..1..1..1..1 %Y A250772 Row 4 of A250769. %K A250772 nonn %O A250772 1,1 %A A250772 _R. H. Hardin_, Nov 27 2014