A207937 Number of n X 7 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 0 1 and 1 1 0 vertically.

35, 1225, 8977, 38207, 121313, 319439, 737575, 1544037, 2994871, 5463725, 9477733, 15759955, 25278917, 39305795, 59479787, 87882217, 127119915, 180418417, 251725529, 345825799, 468466441, 626495255, 828011087, 1082527373, 1401149311

Offset: 1

Author

R. H. Hardin, Feb 21 2012

Keywords

• nonn

Comments

Column 7 of A207938.

Examples

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

Links

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

Crossrefs

Cf. A207938.

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 26 2018: (Start)

G.f.: x*(35 + 945*x + 157*x^2 - 1269*x^3 + 863*x^4 - 191*x^5 + 5*x^6 - x^7) / (1 - x)^8.

a(n) = (1260 + 4974*n - 32165*n^2 - 6041*n^3 + 51940*n^4 + 21091*n^5 + 2905*n^6 + 136*n^7) / 1260.

(End)