A207758 Number of nX4 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 1 and 1 0 1 vertically.

9, 81, 221, 663, 2245, 6459, 17563, 48649, 131269, 344873, 902075, 2342619, 6021103, 15395621, 39219821, 99470227, 251449497, 634148313, 1595707571, 4007571389, 10049914241, 25169768531, 62965428327, 157368593823, 392995561393

Offset: 1

Author

R. H. Hardin Feb 19 2012

Keywords

• nonn

Comments

Column 4 of A207762

Examples

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

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -14*a(n-2) +30*a(n-3) -77*a(n-4) +120*a(n-5) -153*a(n-6) +281*a(n-7) -311*a(n-8) +236*a(n-9) -422*a(n-10) +351*a(n-11) -110*a(n-12) +387*a(n-13) -284*a(n-14) -3*a(n-15) -264*a(n-16) +172*a(n-17) +52*a(n-18) +84*a(n-19) -56*a(n-20) -24*a(n-21) -16*a(n-22) +16*a(n-23) for n>24