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 A200798 #7 Jul 22 2025 15:56:32 %S A200798 51,40148,34679839,30147154218,26207146328784,22781978610167987, %T A200798 19804473216531794553,17216114684815070366422, %U A200798 14966043352402318383229010,13010046560219625329665338289,11309690043874236949034566968117 %N A200798 Number of nX5 0..3 arrays with values 0..3 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors. %C A200798 Column 5 of A200801 %H A200798 R. H. Hardin, <a href="/A200798/b200798.txt">Table of n, a(n) for n = 1..155</a> %e A200798 Some solutions for n=3 %e A200798 ..0..0..0..1..0....0..0..1..1..2....0..0..1..2..2....0..0..1..2..0 %e A200798 ..0..1..0..2..2....0..1..2..3..0....0..1..3..2..3....0..1..2..1..3 %e A200798 ..1..0..0..1..3....0..0..2..3..2....0..1..1..1..3....0..1..1..0..1 %K A200798 nonn %O A200798 1,1 %A A200798 _R. H. Hardin_ Nov 22 2011