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A184045 1/9 the number of (n+1) X 7 0..2 arrays with all 2 X 2 subblocks having the same four values. 1
153, 159, 169, 189, 225, 297, 433, 705, 1233, 2289, 4369, 8529, 16785, 33297, 66193, 131985, 263313, 525969, 1050769, 2100369, 4198545, 8394897, 16785553, 33566865, 67125393, 134242449, 268468369, 536920209, 1073807505, 2147582097, 4295098513 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 6 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*(153 - 300*x - 308*x^2 + 600*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).

a(n) = 3*2^(n/2) + 2^(n+1) + 145 for n even.

a(n) = 2^(n+1) + 2^((n+3)/2) + 145 for n odd.

(End)

EXAMPLE

Some solutions for 5 X 7:

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

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

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

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

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

CROSSREFS

Cf. A184048.

Sequence in context: A346630 A165340 A183985 * A203603 A272767 A104810

Adjacent sequences: A184042 A184043 A184044 * A184046 A184047 A184048

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 08 2011

STATUS

approved

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Last modified February 7 16:06 EST 2023. Contains 360128 sequences. (Running on oeis4.)