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 A232330 #8 Jul 23 2025 07:19:02 %S A232330 1,6,74,734,38986,1047700,318521414,21383016966,41587044818288, %T A232330 6504751614236146,87397564422467956534,30467813258936981061662, %U A232330 2950963661663407494064125726,2230955943109246024221388092190 %N A232330 Number of n X n 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or antidiagonally, with no adjacent elements equal. %C A232330 Diagonal of A232335 %H A232330 R. H. Hardin, <a href="/A232330/b232330.txt">Table of n, a(n) for n = 1..16</a> %e A232330 Some solutions for n=5 %e A232330 ..1..2..0..1..2....0..1..2..1..0....2..1..0..2..1....0..1..2..1..0 %e A232330 ..0..1..2..1..0....0..1..0..2..0....2..1..0..2..0....2..1..2..1..2 %e A232330 ..0..1..2..1..0....0..2..0..1..0....2..1..0..1..2....0..1..0..1..2 %e A232330 ..0..1..2..1..2....0..1..2..1..0....2..1..2..1..2....2..1..2..1..0 %e A232330 ..2..1..2..1..2....2..1..0..2..1....0..1..2..1..0....0..1..0..2..1 %K A232330 nonn %O A232330 1,2 %A A232330 _R. H. Hardin_, Nov 22 2013