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 A209525 #7 Jul 22 2025 21:48:06 %S A209525 203,193676,687132348,4194606038254,31813625228165210, %T A209525 258381047085271692456,2141993311657850070458667, %U A209525 17864055554315250609266434532,149250234599404559427873678874309 %N A209525 Number of nX6 0..7 arrays with every 2X2 subblock containing exactly one value repeat, and new values 0..7 introduced in row major order. %C A209525 Column 6 of A209527 %H A209525 R. H. Hardin, <a href="/A209525/b209525.txt">Table of n, a(n) for n = 1..14</a> %e A209525 Some solutions for n=5 %e A209525 ..0..0..0..0..0..0....0..0..0..1..0..1....0..1..0..0..1..2....0..1..0..0..0..0 %e A209525 ..1..2..1..2..1..3....1..2..1..3..0..2....0..2..2..1..2..0....0..2..2..1..2..3 %e A209525 ..0..0..0..0..0..0....0..0..0..0..1..0....0..1..0..0..2..1....0..1..0..0..0..3 %e A209525 ..4..5..4..5..6..1....1..2..1..2..2..0....1..3..1..2..1..0....1..4..4..1..2..2 %e A209525 ..4..1..1..1..1..0....0..2..0..1..3..0....0..0..0..0..0..2....1..3..2..1..3..4 %K A209525 nonn %O A209525 1,1 %A A209525 _R. H. Hardin_ Mar 10 2012