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 A184473 #7 Jul 22 2025 09:35:37 %S A184473 45585,62213,86575,127689,247879,520289,1219455,3727073,11454631, %T A184473 35847321,132023695,462435665,1581583095,6139850633,22407327775, %U A184473 78976349889,312058001959,1156657902329,4125792115215,16415153428433 %N A184473 1/6 the number of (n+2)X7 0..2 arrays with each 3X3 subblock containing one of one value, four of another, and four of the last. %C A184473 Column 5 of A184477 %H A184473 R. H. Hardin, <a href="/A184473/b184473.txt">Table of n, a(n) for n = 1..28</a> %e A184473 Some solutions with a(1,1)=0 for 4X7 %e A184473 ..0..2..0..0..1..0..0....0..0..0..0..1..1..1....0..2..1..0..0..1..0 %e A184473 ..0..1..0..0..2..1..0....0..1..1..0..0..2..0....0..1..0..1..2..1..1 %e A184473 ..1..1..1..1..1..0..1....1..1..2..1..1..0..0....1..0..1..0..1..0..0 %e A184473 ..0..2..0..0..1..0..0....0..0..0..0..1..1..1....0..2..1..0..0..1..0 %K A184473 nonn %O A184473 1,1 %A A184473 _R. H. Hardin_ Jan 15 2011