A207702 Number of n X 7 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.

40, 1600, 13230, 61254, 206910, 571350, 1369900, 2956980, 5883084, 10965220, 19372210, 32726250, 53222130, 83765514, 128131680, 191146120, 278888400, 398920680, 560542294, 775071790, 1056157830, 1420120350, 1886323380

Offset: 1

Author

R. H. Hardin, Feb 19 2012

Keywords

• nonn

Comments

Column 7 of A207703.

Examples

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

Links

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

Crossrefs

Cf. A207703.

Formula

Empirical: 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).

Conjectures from Colin Barker, Jun 25 2018: (Start)

G.f.: 2*x*(20 + 640*x + 775*x^2 - 1013*x^3 + 259*x^4 + 31*x^5 - 12*x^6) / (1 - x)^8.

a(n) = (n*(162 - 327*n - 881*n^2 + 1296*n^3 + 997*n^4 + 183*n^5 + 10*n^6)) / 36.

(End)