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A206337 Number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock having nonzero determinant and commuting with every horizontal or vertical neighbor. 1
96, 181, 232, 534, 686, 1589, 2042, 4751, 6110, 14239, 18318, 42705, 54942, 128103, 164814, 384297, 494430, 1152879, 1483278, 3458625, 4449822, 10375863, 13349454, 31127577, 40048350, 93382719, 120145038, 280148145, 360435102, 840444423 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A206343.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = a(n-1) + 3*a(n-2) - 3*a(n-3) for n>11.

Empirical g.f.: x*(96 + 85*x - 237*x^2 + 47*x^3 - x^4 - 3*x^5 - 3*x^6 + 2*x^9 + 2*x^10) / ((1 - x)*(1 - 3*x^2)). - Colin Barker, Jun 15 2018

EXAMPLE

Some solutions for n=4:

..3..0..1....0..1..0....1..3..1....0..2..0....0..1..0....1..0..1....0..1..0

..0..3..0....3..0..1....3..1..3....3..0..2....1..0..1....0..1..0....3..0..1

..2..0..3....0..3..0....1..3..1....0..3..0....0..1..0....2..0..1....0..3..0

..0..2..0....1..0..3....3..1..3....1..0..3....2..0..1....0..2..0....3..0..3

..1..0..2....0..1..0....1..3..1....0..1..3....0..2..1....1..0..2....0..3..3

CROSSREFS

Cf. A206343.

Sequence in context: A143847 A178740 A090762 * A161482 A044428 A044809

Adjacent sequences:  A206334 A206335 A206336 * A206338 A206339 A206340

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 06 2012

STATUS

approved

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Last modified April 11 23:58 EDT 2021. Contains 342909 sequences. (Running on oeis4.)