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 A183475 #8 Jul 22 2025 08:58:59 %S A183475 1,15,117,4015,706473,116198719,84056287173 %N A183475 Number of n X n 0..2 arrays with every element equal to either the sum mod 3 of its vertical neighbors or the sum mod 3 of its horizontal neighbors. %C A183475 Diagonal of A183483 %e A183475 Some solutions for 4X4 %e A183475 ..0..1..1..0....0..0..0..0....2..0..1..0....2..1..2..1....0..0..2..2 %e A183475 ..0..0..0..0....1..0..0..0....2..0..1..0....2..0..1..1....2..0..0..0 %e A183475 ..2..0..1..2....1..0..0..1....0..0..0..0....0..0..0..0....2..0..0..0 %e A183475 ..2..0..1..2....0..0..0..1....1..1..0..0....0..2..2..0....0..0..0..0 %K A183475 nonn %O A183475 1,2 %A A183475 _R. H. Hardin_ Jan 05 2011