A207119 Number of nX4 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 0 1 1 vertically

9, 81, 288, 1024, 2560, 6400, 13200, 27225, 49665, 90601, 151704, 254016, 399168, 627264, 938520, 1404225, 2020425, 2907025, 4051080, 5645376, 7660224, 10394176, 13789048, 18292729, 23801505, 30969225, 39622800, 50694400, 63909120, 80568576

Offset

1,1

Comments

Column 4 of A207123

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
..1..1..1..1....1..1..1..1....1..0..1..1....0..1..1..0....0..1..1..0
..1..0..0..0....1..1..1..1....1..1..0..1....1..1..0..0....1..0..1..1
..0..1..1..1....1..1..1..1....0..0..0..0....0..1..1..0....0..0..0..0
..1..0..0..0....1..1..1..0....0..0..0..0....0..0..0..0....1..0..1..1

Crossrefs

Sequence in context: A208165 A207244 A207064 * A207399 A207904 A207748

Adjacent sequences: A207116 A207117 A207118 * A207120 A207121 A207122

Keyword

nonn

Author

R. H. Hardin Feb 15 2012

Status

approved