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 A183582 #8 Feb 20 2025 16:35:30 %S A183582 80,65277,14823037,3724940988,922710498351,229716738097391, %T A183582 57140106100076100,14217486118795912134 %N A183582 Half the number of n X 7 0..3 arrays with each element equal to either the maximum or the minimum of its horizontal and vertical neighbors. %e A183582 Some solutions with a(1,1)<=1 for 3 X 7: %e A183582 ..0..0..0..2..2..0..0....0..0..0..1..1..0..0....0..0..0..2..2..0..0 %e A183582 ..0..0..0..0..2..0..0....0..0..1..1..1..1..1....0..0..0..0..0..0..3 %e A183582 ..0..1..1..1..1..3..3....0..0..0..2..2..1..1....0..1..1..0..3..3..3 %Y A183582 Column 7 of A183584. %K A183582 nonn,more %O A183582 1,1 %A A183582 _R. H. Hardin_, Jan 05 2011