A207705 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.

8, 64, 216, 729, 3321, 15129, 61254, 248004, 1050282, 4447881, 18510693, 77035729, 322765398, 1352327076, 5651244450, 23616005625, 98788590675, 413244551281, 1727977178912, 7225516033024, 30217971381472, 126375166872241

Offset: 1

Author

R. H. Hardin Feb 19 2012

Keywords

• nonn

Comments

Row 4 of A207703

Examples

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

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +14*a(n-3) +48*a(n-4) -65*a(n-5) -41*a(n-6) -103*a(n-7) -351*a(n-8) +353*a(n-9) +286*a(n-10) +103*a(n-11) +629*a(n-12) -480*a(n-13) -280*a(n-14) -16*a(n-15) -367*a(n-16) +216*a(n-17) +46*a(n-18) +2*a(n-19) +53*a(n-20) -28*a(n-21) -2*a(n-22) -2*a(n-24) +a(n-25)