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A184044 1/9 the number of (n+1) X 6 0..2 arrays with all 2 X 2 subblocks having the same four values. 1
81, 87, 97, 117, 153, 225, 361, 633, 1161, 2217, 4297, 8457, 16713, 33225, 66121, 131913, 263241, 525897, 1050697, 2100297, 4198473, 8394825, 16785481, 33566793, 67125321, 134242377, 268468297, 536920137, 1073807433, 2147582025, 4295098441 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 5 of A184048.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

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*(81 - 156*x - 164*x^2 + 312*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).

a(n) = 3*2^(n/2) + 2^(n+1) + 73 for n even.

a(n) = 2^(n+1) + 2^((n+3)/2) + 73 for n odd.

(End)

EXAMPLE

Some solutions for 5 X 6:

..2..0..1..0..2..1....2..1..2..0..2..0....0..2..1..0..1..0....1..2..1..0..1..0

..1..1..2..1..1..0....2..0..2..1..2..1....1..0..0..2..0..2....2..0..2..2..2..2

..2..0..1..0..2..1....2..1..2..0..2..0....0..2..1..0..1..0....1..2..1..0..1..0

..1..1..2..1..1..0....2..0..2..1..2..1....1..0..0..2..0..2....2..0..2..2..2..2

..2..0..1..0..2..1....2..1..2..0..2..0....0..2..1..0..1..0....1..2..1..0..1..0

CROSSREFS

Cf. A184048.

Sequence in context: A345477 A295700 A286898 * A124968 A294577 A044865

Adjacent sequences: A184041 A184042 A184043 * A184045 A184046 A184047

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 08 2011

STATUS

approved

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Last modified February 5 22:19 EST 2023. Contains 360087 sequences. (Running on oeis4.)