A207168 Number of n X 7 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 0 1 vertically.

28, 784, 3808, 11452, 26908, 54208, 98224, 164668, 260092, 391888, 568288, 798364, 1092028, 1460032, 1913968, 2466268, 3130204, 3919888, 4850272, 5937148, 7197148, 8647744, 10307248, 12194812, 14330428, 16734928, 19429984, 22438108, 25782652

Offset: 1

Author

R. H. Hardin, Feb 15 2012

Keywords

• nonn

Comments

Column 7 of A207169.

Examples

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

Links

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

Crossrefs

Cf. A207169.

Formula

Empirical: a(n) = 35*n^4 + 42*n^3 + 7*n^2 - 84*n + 28.

Conjectures from Colin Barker, Jun 20 2018: (Start)

G.f.: 28*x*(1 + 23*x + 6*x^2 - x^3 + x^4) / (1 - x)^5.

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.

(End)