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 A250739 #10 Nov 17 2018 13:10:55 %S A250739 66,70,78,94,126,190,318,574,1086,2110,4158,8254,16446,32830,65598, %T A250739 131134,262206,524350,1048638,2097214,4194366,8388670,16777278, %U A250739 33554494,67108926,134217790,268435518,536870974,1073741886,2147483710,4294967358 %N A250739 Number of (n+1) X (5+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nonincreasing x(i,j)-x(i-1,j) in the j direction. %H A250739 R. H. Hardin, <a href="/A250739/b250739.txt">Table of n, a(n) for n = 1..210</a> %F A250739 Empirical: a(n) = 3*a(n-1) - 2*a(n-2); a(n) = 2^(n+1) + 62. %F A250739 Empirical g.f.: 2*x*(33 - 64*x) / ((1 - x)*(1 - 2*x)). - _Colin Barker_, Nov 17 2018 %e A250739 Some solutions for n=4: %e A250739 ..1..1..1..1..1..1....0..1..1..0..1..0....0..1..1..1..1..0....0..0..0..0..1..0 %e A250739 ..0..0..0..0..0..0....0..1..1..0..1..0....0..1..1..1..1..0....0..0..0..0..1..0 %e A250739 ..1..1..1..1..1..1....0..1..1..0..1..0....0..1..1..1..1..0....0..0..0..0..1..0 %e A250739 ..0..0..0..0..0..0....0..1..1..0..1..0....0..1..1..1..1..0....0..0..0..0..1..0 %e A250739 ..1..1..1..1..1..1....0..1..1..0..1..0....0..1..1..1..1..0....0..0..0..0..1..0 %Y A250739 Column 5 of A250742. %K A250739 nonn %O A250739 1,1 %A A250739 _R. H. Hardin_, Nov 27 2014