A207684 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 1 1 vertically.

9, 81, 166, 436, 964, 2132, 4846, 11301, 25496, 57407, 131250, 299913, 680860, 1542076, 3516426, 8019977, 18194846, 41334779, 94226716, 214384000, 486836482, 1107706812, 2522185912, 5733889814, 13035303238, 29665346161, 67490142684

Offset: 1

Author

R. H. Hardin Feb 19 2012

Keywords

• nonn

Comments

Row 4 of A207682

Examples

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

Links

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

Formula

Empirical: a(n) = 12*a(n-3) +12*a(n-4) +4*a(n-5) -54*a(n-6) -70*a(n-7) -34*a(n-8) +148*a(n-9) +164*a(n-10) +54*a(n-11) -237*a(n-12) -184*a(n-13) -12*a(n-14) +234*a(n-15) +87*a(n-16) -22*a(n-17) -126*a(n-18) -36*a(n-19) +19*a(n-20) +32*a(n-21) +14*a(n-22) -2*a(n-24) for n>26