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A207591 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 1 1 vertically. 1
9, 81, 144, 432, 1098, 3150, 8244, 23202, 61560, 171468, 458640, 1269144, 3412944, 9402156, 25378560, 69694632, 188620632, 516830904, 1401394608, 3833746488, 10409369472, 28443841344, 77305743936, 211065666624, 574042728672 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 4 of A207589.

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-2) + 2*a(n-3) - 10*a(n-4) + 2*a(n-6) for n>8.

Empirical g.f.: 9*x*(1 - x)*(1 + 10*x + 18*x^2 - 8*x^3 - 22*x^4 + 2*x^5 + 4*x^6) / (1 - 8*x^2 - 2*x^3 + 10*x^4 - 2*x^6). - Colin Barker, Jun 24 2018

EXAMPLE

Some solutions for n=4:

  0 1 1 0     0 1 0 0     1 0 1 1     1 0 1 1     0 1 1 0

  1 0 1 1     1 0 1 1     0 1 1 1     0 1 0 1     1 0 1 0

  0 1 0 0     1 1 1 0     1 1 0 0     1 0 1 0     1 1 0 0

  1 0 1 0     0 1 0 0     1 0 1 0     0 1 0 1     0 1 1 0

CROSSREFS

Cf. A207589.

Sequence in context: A175370 A207695 A158028 * A207924 A343134 A343104

Adjacent sequences:  A207588 A207589 A207590 * A207592 A207593 A207594

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 19 2012

STATUS

approved

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Last modified July 25 16:03 EDT 2021. Contains 346291 sequences. (Running on oeis4.)