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A206982 Number of n X 3 0..1 arrays avoiding the patterns 0 1 0 or 1 0 1 in any row, column, diagonal or antidiagonal. 1
6, 36, 58, 158, 420, 1066, 2754, 7140, 18430, 47602, 123028, 317870, 821262, 2121988, 5482746, 14166078, 36601876, 94570810, 244348930, 631340852, 1631238222, 4214740594, 10889910564, 28136999454, 72699470734, 187838545012 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A206987.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) + a(n-2) + 2*a(n-3) - a(n-4) - 2*a(n-5) for n>7.

Empirical g.f.: 2*x*(1 - x)*(3 + 15*x + 5*x^2 + 2*x^3 - 8*x^4 - 8*x^5) / (1 - 2*x - x^2 - 2*x^3 + x^4 + 2*x^5). - Colin Barker, Jun 17 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Cf. A206987.

Sequence in context: A132633 A047792 A178909 * A121026 A207694 A208496

Adjacent sequences:  A206979 A206980 A206981 * A206983 A206984 A206985

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 14 2012

STATUS

approved

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Last modified January 18 00:56 EST 2021. Contains 340249 sequences. (Running on oeis4.)