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 A232298 #6 Jul 23 2025 07:16:30 %S A232298 1,355,17759,718483,31119789,1370434057,60054788123,2629547976059, %T A232298 115168967578383,5044363984412427,220938351417726213, %U A232298 9676874008509774099,423837490846852109695,18563663237964339458229,813070077580205734910151 %N A232298 Number of 4Xn 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or antidiagonally. %C A232298 Row 4 of A232295 %H A232298 R. H. Hardin, <a href="/A232298/b232298.txt">Table of n, a(n) for n = 1..210</a> %e A232298 Some solutions for n=3 %e A232298 ..2..1..0....2..0..1....2..1..0....2..1..2....2..2..1....2..2..1....2..2..2 %e A232298 ..0..2..2....2..2..0....2..0..2....2..2..1....1..2..1....0..1..2....2..2..0 %e A232298 ..2..1..1....1..1..2....1..2..2....2..0..1....2..1..0....1..2..2....2..1..0 %e A232298 ..2..2..1....1..2..1....1..1..0....2..2..1....0..2..1....2..2..1....2..2..2 %K A232298 nonn %O A232298 1,2 %A A232298 _R. H. Hardin_, Nov 22 2013