A184047 1/9 the number of (n+1) X 9 0..2 arrays with all 2 X 2 subblocks having the same four values.

561, 567, 577, 597, 633, 705, 841, 1113, 1641, 2697, 4777, 8937, 17193, 33705, 66601, 132393, 263721, 526377, 1051177, 2100777, 4198953, 8395305, 16785961, 33567273, 67125801, 134242857, 268468777, 536920617, 1073807913, 2147582505, 4295098921

Offset: 1

Author

R. H. Hardin, Jan 08 2011

Keywords

• nonn

Comments

Column 8 of A184048.

Examples

			Some solutions for 5 X 9:
..2..0..2..0..0..1..0..1..2....1..1..0..0..0..0..1..0..1
..0..1..0..1..2..0..2..0..0....0..0..1..1..1..1..0..1..0
..2..0..2..0..0..1..0..1..2....1..1..0..0..0..0..1..0..1
..0..1..0..1..2..0..2..0..0....0..0..1..1..1..1..0..1..0
..2..0..2..0..0..1..0..1..2....1..1..0..0..0..0..1..0..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..158

Crossrefs

Cf. A184048.

Formula

Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 4*a(n-4).

Conjectures from Colin Barker, Apr 10 2018: (Start)

G.f.: x*(561 - 1116*x - 1124*x^2 + 2232*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).

a(n) = 3*2^(n/2) + 2^(n+1) + 553 for n even.

a(n) = 2^(n+1) + 2^((n+3)/2) + 553 for n odd.

(End)