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

1,1

Comments

Column 8 of A184048.

Links

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

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)

Example

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

Crossrefs

Cf. A184048.

Sequence in context: A274443 A247906 A278338 * A344673 A344706 A259172

Adjacent sequences: A184044 A184045 A184046 * A184048 A184049 A184050

Keyword

nonn

Author

R. H. Hardin, Jan 08 2011

Status

approved