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A206199 Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly one clockwise edge increases. 1
256, 480, 1768, 7388, 29724, 117084, 468968, 1878808, 7493008, 29925508, 119605588, 477741796, 1908251600, 7623408272, 30453658424, 121651754668, 485967430220, 1941313945708, 7755000190904, 30979095429960, 123753089725152 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A206206.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + 17*a(n-3) - 5*a(n-4) + 2*a(n-5) for n>6.

Empirical g.f.: 4*x*(64 - 72*x + 82*x^2 - 567*x^3 + 170*x^4 - 64*x^5) / (1 - 3*x - 17*x^3 + 5*x^4 - 2*x^5). - Colin Barker, Jun 14 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Cf. A206206.

Sequence in context: A223693 A223064 A206206 * A271811 A255998 A309092

Adjacent sequences:  A206196 A206197 A206198 * A206200 A206201 A206202

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 04 2012

STATUS

approved

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Last modified September 24 02:30 EDT 2021. Contains 347618 sequences. (Running on oeis4.)