A207904 Number of nX4 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 0 and 0 1 1 vertically

9, 81, 289, 841, 2209, 5041, 11025, 22801, 45369, 88209, 167281, 312481, 576081, 1050625, 1901641, 3418801, 6115729, 10896601, 19351201, 34281025, 60606225, 106977649, 188595289, 332150625, 584527329, 1028035969, 1807185121

Offset

1,1

Comments

Column 4 of A207908

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -3*a(n-2) -4*a(n-3) -a(n-4) +14*a(n-5) -6*a(n-6) -5*a(n-7) -3*a(n-8) +7*a(n-9) -4*a(n-10) +3*a(n-11) -2*a(n-14) +a(n-15)

Example

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

Crossrefs

Sequence in context: A207064 A207119 A207399 * A207748 A208035 A207124

Adjacent sequences: A207901 A207902 A207903 * A207905 A207906 A207907

Keyword

nonn

Author

R. H. Hardin Feb 21 2012

Status

approved