A207678 Number of n X 4 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 1 1 vertically.

9, 81, 164, 436, 1030, 2032, 4174, 8266, 16060, 30670, 57888, 109188, 202628, 375252, 692182, 1267634, 2319308, 4224978, 7679364, 13935174, 25221442, 45611766, 82350810, 148518712, 267668550, 481894280, 867169926, 1559501878, 2803131788

Offset

1,1

Comments

Column 4 of A207682.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +2*a(n-2) +a(n-3) -12*a(n-4) -3*a(n-5) +27*a(n-7) +8*a(n-8) -2*a(n-9) -33*a(n-10) -15*a(n-11) +19*a(n-13) +23*a(n-14) -4*a(n-15) +a(n-16) -19*a(n-17) +4*a(n-18) -4*a(n-19) +7*a(n-20) -a(n-21) +a(n-22) -a(n-23) for n>28.

Example

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

Crossrefs

Cf. A207682.

Sequence in context: A343104 A043180 A207875 * A207684 A207510 A208104

Adjacent sequences: A207675 A207676 A207677 * A207679 A207680 A207681

Keyword

nonn

Author

R. H. Hardin, Feb 19 2012

Status

approved