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 A205410 #7 Jul 22 2025 18:50:34 %S A205410 33322,549414,10331386,151598017,2553087985,45661264026,735422130329, %T A205410 12286397087182,212128668698876,3518160933737460,58829708185415817, %U A205410 999828369246325845,16744112843227770105,280613932821800402695 %N A205410 Number of (n+2)X5 0..2 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly two ways, and new values 0..2 introduced in row major order. %C A205410 Column 3 of A205415 %H A205410 R. H. Hardin, <a href="/A205410/b205410.txt">Table of n, a(n) for n = 1..210</a> %e A205410 Some solutions for n=3 %e A205410 ..0..0..0..0..1....0..1..1..0..1....0..0..1..2..2....0..0..1..0..1 %e A205410 ..0..1..2..1..1....1..1..1..1..1....1..2..1..0..1....1..0..1..1..2 %e A205410 ..1..1..1..1..1....2..2..1..0..0....1..1..1..1..1....0..0..1..2..1 %e A205410 ..1..1..2..2..1....0..0..0..0..0....1..2..2..2..2....1..1..1..1..1 %e A205410 ..1..2..2..2..1....1..1..1..0..1....0..0..0..1..2....2..2..2..2..2 %K A205410 nonn %O A205410 1,1 %A A205410 _R. H. Hardin_ Jan 26 2012