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 A232157 #7 Jul 23 2025 06:55:58 %S A232157 8,218,1284,7770,46702,286770,1767266,10830650,66701686,410364610, %T A232157 2522566124,15524673872,95489164864,587352257166,3613537440642, %U A232157 22227593479382,136734516680534,841147631122416,5174280907720634 %N A232157 Number of nX4 0..3 arrays with every 0 next to a 1, every 1 next to a 2 and every 2 next to a 3 horizontally, vertically or antidiagonally, and no adjacent values equal. %C A232157 Column 4 of A232161 %H A232157 R. H. Hardin, <a href="/A232157/b232157.txt">Table of n, a(n) for n = 1..210</a> %H A232157 R. H. Hardin, <a href="/A232157/a232157.txt">Empirical recurrence of order 94</a> %F A232157 Empirical recurrence of order 94 (see link above) %e A232157 Some solutions for n=5 %e A232157 ..1..3..2..3....1..3..2..1....3..0..1..3....1..3..0..2....0..3..1..2 %e A232157 ..2..0..1..2....2..1..3..0....1..2..0..1....2..1..3..1....1..2..0..3 %e A232157 ..1..3..0..1....3..0..2..1....3..1..3..2....0..2..0..3....3..1..2..1 %e A232157 ..2..1..2..0....2..1..0..3....2..0..1..3....1..3..2..1....2..0..3..2 %e A232157 ..0..3..1..3....0..3..1..2....3..2..0..2....0..1..3..2....1..2..0..1 %K A232157 nonn %O A232157 1,1 %A A232157 _R. H. Hardin_, Nov 19 2013