A207678 Number of nX4 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

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