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 A185538 #8 Jul 22 2025 09:53:42 %S A185538 11,12105,4403225,2241330570,994633804270,468362874353295 %N A185538 1/6 the number of nX5 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors. %C A185538 Column 5 of A185540 %e A185538 Some solutions for 3X5 with a(1,1)=0 %e A185538 ..0..0..0..4..4....0..0..3..3..5....0..0..0..3..4....0..0..0..0..1 %e A185538 ..0..3..3..2..4....3..3..4..3..5....0..3..1..3..4....0..3..2..1..1 %e A185538 ..0..0..0..2..2....0..0..4..4..5....0..3..1..5..5....0..3..2..5..5 %K A185538 nonn %O A185538 1,1 %A A185538 _R. H. Hardin_ Jan 30 2011