A208122 Number of 7Xn 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 0 1 1 vertically

20, 400, 1260, 3969, 34713, 303601, 1432600, 6760000, 45648200, 308248249, 1680152229, 9157915809, 56635398540, 350250912400, 2009057864020, 11524062773521, 69120684953057, 414582008296369, 2421339816495600

Offset

1,1

Comments

Row 7 of A208118

Links

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

Formula

Empirical: a(n) = a(n-1) -12*a(n-2) +55*a(n-3) +805*a(n-4) +900*a(n-5) +10320*a(n-6) -123840*a(n-8) -129600*a(n-9) -1391040*a(n-10) -1140480*a(n-11) +2985984*a(n-12) -2985984*a(n-13) +35831808*a(n-14)

Example

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

Crossrefs

Sequence in context: A171325 A075843 A208072 * A207372 A208017 A208559

Adjacent sequences: A208119 A208120 A208121 * A208123 A208124 A208125

Keyword

nonn

Author

R. H. Hardin Feb 23 2012

Status

approved