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A206145 Number of (n+1) X 4 0..2 arrays with every 2 X 3 or 3 X 2 subblock having exactly three counterclockwise and three clockwise edge increases. 1
162, 1122, 7812, 54450, 379602, 2646540, 18451530, 128643282, 896895828, 6253122402, 43596523890, 303953253948, 2119150161594, 14774631788466, 103008153195972, 718168802906322, 5007044718948114, 34908919346114028 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A206150.

LINKS

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

FORMULA

Empirical: a(n) = 9*a(n-1) - 15*a(n-2) + 6*a(n-3).

Empirical g.f.: 6*x*(27 - 56*x + 24*x^2) / (1 - 9*x + 15*x^2 - 6*x^3). - Colin Barker, Jun 13 2018

EXAMPLE

Some solutions for n=4:

  2 1 2 1    2 0 2 0    0 1 2 0    0 1 2 1    0 2 0 2

  1 2 0 2    0 1 0 1    1 0 1 2    1 0 1 2    1 0 1 0

  2 0 1 0    1 2 1 2    0 2 0 1    2 1 2 0    2 1 2 1

  1 2 0 1    0 1 0 1    1 0 1 0    0 2 0 1    0 2 0 2

  2 0 2 0    2 0 1 0    2 1 2 1    2 0 1 2    1 0 1 0

CROSSREFS

Cf. A206150.

Sequence in context: A186844 A319915 A302731 * A342850 A304166 A213288

Adjacent sequences:  A206142 A206143 A206144 * A206146 A206147 A206148

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 04 2012

STATUS

approved

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Last modified January 19 15:13 EST 2022. Contains 350466 sequences. (Running on oeis4.)