A206780 Number of nX3 0..1 arrays avoiding 0 0 1 horizontally and 0 1 1 vertically

7, 49, 230, 1020, 4120, 16109, 61003, 227197, 834806, 3041436, 11009856, 39680145, 142545383, 510891025, 1827957230, 6532356532, 23322885552, 83216416445, 296774223739, 1058010185133, 3770863749966, 13437211488900, 47875876583016

Offset

1,1

Comments

Column 3 of A206785

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -10*a(n-2) -23*a(n-3) +57*a(n-4) +6*a(n-5) -75*a(n-6) +21*a(n-7) +34*a(n-8) -13*a(n-9) -5*a(n-10) +2*a(n-11)

Example

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

Crossrefs

Sequence in context: A188502 A188517 A206878 * A181219 A141783 A181479

Adjacent sequences: A206777 A206778 A206779 * A206781 A206782 A206783

Keyword

nonn

Author

R. H. Hardin Feb 12 2012

Status

approved