A207841 Number of nX4 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 0 and 1 1 1 vertically.

10, 100, 180, 780, 2816, 9672, 35952, 130152, 462660, 1691356, 6097536, 21894544, 79589224, 286756120, 1033424532, 3745763500, 13500573120, 48729856032, 176324800080, 635878928776, 2296600176396, 8301910089028, 29954416843008

Offset: 1

Author

R. H. Hardin Feb 21 2012

Keywords

• nonn

Comments

Column 4 of A207845

Examples

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

Links

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

Formula

Empirical: a(n) = 3*a(n-2) +36*a(n-3) +6*a(n-4) +2*a(n-5) -84*a(n-6) +34*a(n-7) +89*a(n-8) -260*a(n-9) +91*a(n-10) -42*a(n-11) +84*a(n-12) -2*a(n-13) +8*a(n-14) +36*a(n-15) +3*a(n-16) +a(n-18) for n>20