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

Author

R. H. Hardin Feb 21 2012

Keywords

• nonn

Comments

Column 4 of A207908

Examples

			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
		

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)