A207389 Number of n X 6 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.

21, 441, 2307, 7561, 19319, 42167, 82477, 148743, 251937, 405885, 627663, 938013, 1361779, 1928363, 2672201, 3633259, 4857549, 6397665, 8313339, 10672017, 13549455, 17030335, 21208901, 26189615, 32087833, 39030501, 47156871, 56619237

Offset: 1

Author

R. H. Hardin, Feb 17 2012

Keywords

• nonn

Comments

Column 6 of A207391.

Examples

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

Links

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

Crossrefs

Cf. A207391.

Formula

Empirical: a(n) = (1/36)*n^6 + (113/60)*n^5 + (151/9)*n^4 + (95/4)*n^3 - (605/36)*n^2 - (229/30)*n + 3.

Conjectures from Colin Barker, Jun 22 2018: (Start)

G.f.: x*(21 + 294*x - 339*x^2 - 62*x^3 + 139*x^4 - 36*x^5 + 3*x^6) / (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)