A207914 Number of nX4 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 0 and 1 0 1 vertically

9, 81, 271, 1309, 5371, 23637, 101069, 438103, 1887667, 8151773, 35161937, 151744767, 654767065, 2825582407, 12192964863, 52615498559, 227045509685, 979746980809, 4227807834119, 18243882203687, 78726167982599

Offset

1,1

Comments

Column 4 of A207918

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -12*a(n-2) +17*a(n-3) +5*a(n-4) +51*a(n-5) +36*a(n-6) -399*a(n-7) +554*a(n-8) -625*a(n-9) -854*a(n-10) -4016*a(n-11) +210*a(n-12) +9416*a(n-13) +9774*a(n-14) +4886*a(n-15) -6673*a(n-16) -6888*a(n-17) -6416*a(n-18) -2847*a(n-19) -607*a(n-20) +1513*a(n-21) +1902*a(n-22) +1033*a(n-23) +100*a(n-24) -185*a(n-25) -162*a(n-26) -18*a(n-27) +8*a(n-29)

Example

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

Crossrefs

Sequence in context: A207753 A207107 A207463 * A208040 A208029 A208160

Adjacent sequences: A207911 A207912 A207913 * A207915 A207916 A207917

Keyword

nonn

Author

R. H. Hardin Feb 21 2012

Status

approved