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A186461 Number of (n+1) X 9 binary arrays with every 2 X 2 subblock commuting with each of its horizontal and vertical 2 X 2 subblock neighbors. 1
359, 457, 846, 1493, 2285, 3677, 5633, 9477, 13245, 20281, 27573, 43177, 62025, 98157, 144825, 224381, 333321, 511281, 765293, 1167881, 1755461, 2669577, 4022697, 6104941, 9213769, 13965837, 21097609, 31954865, 48300653, 73123993 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 8 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>14.

Empirical g.f.: x*(359 - 261*x - 68*x^2 + 519*x^3 - 505*x^4 + 244*x^5 + 30*x^6 + 641*x^7 - 1432*x^8 - 12*x^9 - 1624*x^10 + 1200*x^11 - 780*x^12 + 1936*x^13) / ((1 - x)*(1 - x - x^2 + x^3 - x^4)). - Colin Barker, Apr 18 2018

EXAMPLE

Some solutions for 3 X 9:

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

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

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

CROSSREFS

Cf. A186462.

Sequence in context: A145533 A273806 A292618 * A142381 A054826 A101796

Adjacent sequences:  A186458 A186459 A186460 * A186462 A186463 A186464

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 22 2011

STATUS

approved

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Last modified May 9 04:55 EDT 2021. Contains 343687 sequences. (Running on oeis4.)