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A206130 Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly three counterclockwise and three clockwise edge increases. 1
256, 564, 3092, 19660, 125236, 797996, 5085012, 32403084, 206481524, 1315758316, 8384382100, 53427641420, 340455961524, 2169481164972, 13824544308692, 88093885500940, 561359021271796, 3577137606898796, 22794527163204372 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A206137.

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-1) - 11*a(n-2) + 4*a(n-3) for n > 5.

Empirical g.f.: 4*x*(64 - 371*x + 349*x^2 + 26*x^3 - 72*x^4) / ((1 - x)*(1 - 7*x + 4*x^2)). - Colin Barker, Jun 13 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Cf. A206137.

Sequence in context: A235060 A260243 A206137 * A110297 A134608 A134609

Adjacent sequences:  A206127 A206128 A206129 * A206131 A206132 A206133

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 04 2012

STATUS

approved

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Last modified June 28 21:04 EDT 2022. Contains 354907 sequences. (Running on oeis4.)