A207404 Number of 4Xn 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically

8, 64, 216, 729, 1782, 4356, 8910, 18225, 33210, 60516, 101598, 170569, 269276, 425104, 639612, 962361, 1393020, 2016400, 2827220, 3964081, 5411538, 7387524, 9858186, 13155129, 17213742, 22524516, 28974330, 37271025, 47228280, 59845696

Offset

1,1

Comments

Row 4 of A207403

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +6*a(n-2) -14*a(n-3) -14*a(n-4) +42*a(n-5) +14*a(n-6) -70*a(n-7) +70*a(n-9) -14*a(n-10) -42*a(n-11) +14*a(n-12) +14*a(n-13) -6*a(n-14) -2*a(n-15) +a(n-16)

Example

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

Crossrefs

Sequence in context: A207071 A117219 A267783 * A207705 A264060 A207250

Adjacent sequences: A207401 A207402 A207403 * A207405 A207406 A207407

Keyword

nonn

Author

R. H. Hardin Feb 17 2012

Status

approved