A207953 Number of 7Xn 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 1 0 and 1 0 1 vertically

42, 1764, 14406, 117649, 524104, 2334784, 7513176, 24176889, 63380130, 166152100, 377999250, 859955625, 1762784400, 3613452544, 6837439440, 12937925025, 22975807530, 40801576036, 68811074046, 116048554281, 187501438872

Offset

1,1

Comments

Row 7 of A207949

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +12*a(n-2) -26*a(n-3) -65*a(n-4) +156*a(n-5) +208*a(n-6) -572*a(n-7) -429*a(n-8) +1430*a(n-9) +572*a(n-10) -2574*a(n-11) -429*a(n-12) +3432*a(n-13) -3432*a(n-15) +429*a(n-16) +2574*a(n-17) -572*a(n-18) -1430*a(n-19) +429*a(n-20) +572*a(n-21) -208*a(n-22) -156*a(n-23) +65*a(n-24) +26*a(n-25) -12*a(n-26) -2*a(n-27) +a(n-28)

Example

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

Crossrefs

Sequence in context: A207471 A207523 A207258 * A207862 A207812 A208286

Adjacent sequences: A207950 A207951 A207952 * A207954 A207955 A207956

Keyword

nonn

Author

R. H. Hardin Feb 21 2012

Status

approved