A207462 Number of n X 3 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 0 and 1 0 1 vertically.

6, 36, 98, 358, 1152, 3910, 12994, 43596, 145678, 487502, 1630196, 5453054, 18238998, 61008244, 204063338, 682563198, 2283064944, 7636504950, 25542956650, 85437392020, 285775310062, 955875582398, 3197260259292, 10694355621414

Offset: 1

Author

R. H. Hardin, Feb 18 2012

Keywords

• nonn

Comments

Column 3 of A207467.

Examples

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

Links

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

Crossrefs

Cf. A207467.

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) -4*a(n-3) +11*a(n-4) +15*a(n-5) +4*a(n-6) -23*a(n-7) -17*a(n-8) +4*a(n-9) -7*a(n-10) +a(n-11) +a(n-12).