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A186457 Number of (n+1) X 5 binary arrays with every 2 X 2 subblock commuting with each of its horizontal and vertical 2 X 2 subblock neighbors. 1
61, 88, 162, 309, 449, 673, 945, 1493, 2201, 3473, 5177, 7993, 11949, 18289, 27473, 41857, 63041, 95765, 144473, 219105, 330905, 501353, 757677, 1147281, 1734561, 2625569, 3970577, 6008917, 9088537, 13752497, 20802745, 31475673, 47614509 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A186462.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) - 2*a(n-3) + 2*a(n-4) - a(n-5) for n>10.

Empirical g.f.: x*(61 - 34*x - 14*x^2 + 107*x^3 - 115*x^4 - 16*x^5 - 19*x^6 + 45*x^7 - 28*x^8 + 64*x^9) / ((1 - x)*(1 - x - x^2 + x^3 - x^4)). - Colin Barker, Apr 17 2018

EXAMPLE

Some solutions for 3 X 5:

..0..0..0..0..0....1..0..0..0..0....1..0..0..1..1....1..0..0..0..0

..0..0..0..0..0....0..1..0..0..0....0..0..0..0..1....1..0..0..0..0

..1..0..0..0..0....1..0..1..0..0....0..0..0..0..0....0..1..0..0..0

CROSSREFS

Cf. A186462.

Sequence in context: A325076 A253232 A245759 * A103812 A047272 A123207

Adjacent sequences:  A186454 A186455 A186456 * A186458 A186459 A186460

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 22 2011

STATUS

approved

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Last modified February 21 04:39 EST 2020. Contains 332086 sequences. (Running on oeis4.)