A207256 Number of 5 X n 0..1 arrays avoiding 0 0 1 and 1 0 1 horizontally and 0 1 0 and 1 0 1 vertically.

16, 256, 1232, 3776, 9072, 18688, 34608, 59264, 95568, 146944, 217360, 311360, 434096, 591360, 789616, 1036032, 1338512, 1705728, 2147152, 2673088, 3294704, 4024064, 4874160, 5858944, 6993360, 8293376, 9776016, 11459392, 13362736

Offset: 1

Author

R. H. Hardin, Feb 16 2012

Keywords

• nonn

Comments

Row 5 of A207254.

Examples

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

Links

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

Crossrefs

Cf. A207254.

Formula

Empirical: a(n) = (4/15)*n^5 + (32/3)*n^4 + (44/3)*n^3 - (32/3)*n^2 + (16/15)*n.

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

G.f.: 16*x*(1 + 10*x - 4*x^2 - 6*x^3 + x^4) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.

(End)