cp's OEIS Frontend

A209459 Number of nX2 0..6 arrays with every 2X2 subblock containing exactly one value repeat, and new values 0..6 introduced in row major order.

%I A209459 #7 Jul 22 2025 21:43:58
%S A209459 2,6,57,700,10676,192994,3966581,89157292,2122477292,52308803176,
%T A209459 1315354516436,33456562887760,856485703088336,22005434702222368,
%U A209459 566526069249475088,14601678389694957760,376583948372941600448
%N A209459 Number of nX2 0..6 arrays with every 2X2 subblock containing exactly one value repeat, and new values 0..6 introduced in row major order.
%C A209459 Column 2 of A209465
%H A209459 R. H. Hardin, <a href="/A209459/b209459.txt">Table of n, a(n) for n = 1..210</a>
%F A209459 Empirical: a(n) = 44*a(n-1) -456*a(n-2) -1360*a(n-3) +25892*a(n-4) +16752*a(n-5) -259776*a(n-6) -406080*a(n-7) -129600*a(n-8) for n>9
%e A209459 Some solutions for n=4
%e A209459 ..0..0....0..0....0..0....0..0....0..1....0..0....0..0....0..0....0..0....0..0
%e A209459 ..1..2....1..2....1..2....1..2....0..2....1..2....1..2....1..2....1..2....1..2
%e A209459 ..0..0....0..0....2..3....0..1....1..0....3..1....3..1....0..1....0..0....1..0
%e A209459 ..3..4....1..2....0..0....1..2....0..2....0..0....4..4....0..2....3..1....2..0
%K A209459 nonn
%O A209459 1,1
%A A209459 _R. H. Hardin_ Mar 09 2012