A207258 Number of 7 X n 0..1 arrays avoiding 0 0 1 and 1 0 1 horizontally and 0 1 0 and 1 0 1 vertically.

42, 1764, 14406, 64176, 206514, 541380, 1231650, 2524704, 4777290, 8483748, 14307678, 23117136, 36023442, 54423684, 80047002, 115004736, 161844522, 223608420, 303895158, 406926576, 537618354, 701655108, 905569938, 1156828512

Offset

1,1

Comments

Row 7 of A207254.

Links

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

Formula

Empirical: a(n) = (1/60)*n^7 + (77/20)*n^6 + (2527/60)*n^5 + (119/4)*n^4 - (644/15)*n^3 + (42/5)*n^2 + (4/5)*n.

Conjectures from Colin Barker, Jun 21 2018: (Start)

G.f.: 42*x*(1 + 34*x + 35*x^2 - 96*x^3 + 15*x^4 + 14*x^5 - x^6) / (1 - x)^8.

a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.

(End)

Example

Some solutions for n=4:
..1..0..0..0....1..0..0..0....1..1..1..0....0..0..0..0....1..0..0..0
..1..1..0..0....1..0..0..0....0..1..1..1....0..1..1..1....1..1..0..0
..1..1..0..0....1..0..0..0....0..1..1..1....0..1..1..1....0..1..0..0
..0..1..1..0....0..1..1..0....1..1..0..0....1..1..0..0....0..0..0..0
..0..1..1..0....0..1..1..0....1..0..0..0....1..0..0..0....1..0..0..0
..0..1..0..0....0..1..0..0....0..0..0..0....1..0..0..0....1..1..0..0
..0..1..0..0....0..1..0..0....0..0..0..0....0..1..0..0....0..1..0..0

Crossrefs

Cf. A207254.

Sequence in context: A208702 A207471 A207523 * A207953 A207862 A207812

Adjacent sequences: A207255 A207256 A207257 * A207259 A207260 A207261

Keyword

nonn

Author

R. H. Hardin, Feb 16 2012

Status

approved