A207875 Number of nX4 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 0 and 1 1 1 vertically

9, 81, 164, 400, 824, 1940, 4200, 9276, 21004, 46026, 102674, 228630, 506868, 1128070, 2505156, 5569740, 12380188, 27502690, 61145106, 135886522, 301975112, 671190932, 1491685306, 3315241202, 7368059728, 16375432824, 36394465410

Offset

1,1

Comments

Column 4 of A207879

Links

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

Formula

Empirical: a(n) = 2*a(n-2) +7*a(n-3) +4*a(n-4) -3*a(n-5) -17*a(n-6) -5*a(n-7) +7*a(n-8) +2*a(n-9) -13*a(n-10) -a(n-11) -2*a(n-12) for n>14

Example

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

Crossrefs

Sequence in context: A343134 A343104 A043180 * A207678 A207684 A207510

Adjacent sequences: A207872 A207873 A207874 * A207876 A207877 A207878

Keyword

nonn

Author

R. H. Hardin Feb 21 2012

Status

approved