cp's OEIS Frontend

A209497 Number of n X 2 0..4 arrays with every 2 X 2 subblock containing exactly one value repeat, and new values 0..4 introduced in row major order.

%I A209497 #8 Jul 10 2018 06:15:59
%S A209497 2,6,57,690,9393,133380,1920126,27760512,401882796,5820335088,
%T A209497 84304518360,1221153876288,17688664980912,256224877720896,
%U A209497 3711487617186912,53761934301895680,778756709322725568
%N A209497 Number of n X 2 0..4 arrays with every 2 X 2 subblock containing exactly one value repeat, and new values 0..4 introduced in row major order.
%C A209497 Column 2 of A209503.
%H A209497 R. H. Hardin, <a href="/A209497/b209497.txt">Table of n, a(n) for n = 1..210</a>
%F A209497 Empirical: a(n) = 16*a(n-1) - 10*a(n-2) - 168*a(n-3) - 72*a(n-4) for n>5.
%F A209497 Empirical g.f.: x*(2 - 26*x - 19*x^2 + 174*x^3 + 75*x^4) / ((1 - 4*x - 2*x^2)*(1 - 12*x - 36*x^2)). - _Colin Barker_, Jul 10 2018
%e A209497 Some solutions for n=4.
%e A209497 ..0..0....0..0....0..1....0..0....0..0....0..0....0..0....0..0....0..1....0..0
%e A209497 ..1..2....1..2....0..2....1..2....1..2....1..2....1..2....1..2....1..2....1..2
%e A209497 ..3..1....2..0....1..0....0..1....2..3....0..2....1..0....0..1....0..2....2..3
%e A209497 ..2..1....0..3....2..0....0..2....2..1....3..2....2..0....2..1....1..0....4..2
%Y A209497 Cf. A209503.
%K A209497 nonn
%O A209497 1,1
%A A209497 _R. H. Hardin_, Mar 09 2012