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A207066 Number of n X 6 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically. 1
21, 441, 2499, 8799, 23856, 54684, 111426, 208026, 362943, 599907, 948717, 1446081, 2136498, 3073182, 4319028, 5947620, 8044281, 10707165, 14048391, 18195219, 23291268, 29497776, 36994902, 45983070, 56684355, 69343911, 84231441 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 6 of A207068.

LINKS

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

FORMULA

Empirical: a(n) = (7/120)*n^6 + (147/40)*n^5 + (49/3)*n^4 + (91/8)*n^3 - (707/120)*n^2 - (91/20)*n.

Conjectures from Colin Barker, Jun 18 2018: (Start)

G.f.: 21*x*(1 + 14*x - 7*x^2 - 8*x^3 + 2*x^4) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)

EXAMPLE

Some solutions for n=4:

..0..0..0..0..0..0....0..1..1..1..0..0....1..0..1..1..1..0....1..1..1..1..1..0

..1..0..1..1..1..0....1..0..1..1..1..0....0..1..1..1..1..0....0..0..0..0..0..0

..0..0..0..0..0..0....1..0..0..0..0..0....0..1..1..1..0..0....0..0..0..0..0..0

..0..0..0..0..0..0....1..0..0..0..0..0....0..0..0..0..0..0....0..0..0..0..0..0

CROSSREFS

Cf. A207068.

Sequence in context: A207517 A207246 A208167 * A207121 A207440 A188691

Adjacent sequences:  A207063 A207064 A207065 * A207067 A207068 A207069

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 14 2012

STATUS

approved

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Last modified February 27 19:10 EST 2020. Contains 332308 sequences. (Running on oeis4.)