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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
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: A372945 A047792 A178909 * A121026 A207694 A208496
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 14 2012
STATUS
approved

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Last modified May 27 08:22 EDT 2024. Contains 372850 sequences. (Running on oeis4.)