A206878 Number of nX3 0..1 arrays avoiding 0 1 0 horizontally and 1 0 1 vertically

7, 49, 230, 1011, 4705, 22412, 105936, 497727, 2339729, 11013295, 51846666, 244013222, 1148355280, 5404522372, 25435928407, 119711433603, 563405871570, 2651594982047, 12479394172896, 58732688555813, 276417903263710

Offset

1,1

Comments

Column 3 of A206883

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -7*a(n-2) +24*a(n-3) +8*a(n-4) +11*a(n-5) +32*a(n-6) -22*a(n-7) -44*a(n-8) +11*a(n-9) +13*a(n-10) -a(n-11) -a(n-12)

Example

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

Crossrefs

Sequence in context: A223632 A188502 A188517 * A206780 A181219 A141783

Adjacent sequences: A206875 A206876 A206877 * A206879 A206880 A206881

Keyword

nonn

Author

R. H. Hardin Feb 13 2012

Status

approved