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 A183361 #7 Jul 22 2025 08:51:48 %S A183361 8748,589824,314928,435600,802944,1679616,3852288,9437184,23003136, %T A183361 47775744,95551488,191102976,389283840,807469056,1695744000, %U A183361 3588489216,7596343296,16057958400,33888927744,71430045696,150473539584 %N A183361 One quarter the number of nX9 1..4 arrays with no two neighbors of any element equal to each other. %C A183361 Column 9 of A183362 %H A183361 R. H. Hardin, <a href="/A183361/b183361.txt">Table of n, a(n) for n = 1..26</a> %e A183361 Some solutions for 5X9 with a(1,1)=1 %e A183361 ..1..1..2..3..3..1..2..3..4....1..1..2..4..4..2..2..3..1 %e A183361 ..2..4..4..1..2..4..4..1..1....2..4..3..3..1..1..4..3..2 %e A183361 ..2..3..3..1..2..3..3..2..2....2..4..1..2..2..3..4..1..2 %e A183361 ..4..1..2..4..4..1..1..4..3....3..3..1..4..4..3..2..1..3 %e A183361 ..3..1..2..3..3..2..2..4..1....4..2..2..3..1..1..2..4..4 %K A183361 nonn %O A183361 1,1 %A A183361 _R. H. Hardin_ Jan 04 2011