A207271 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 1 and 1 0 1 vertically.

9, 81, 193, 611, 1602, 3513, 8327, 17568, 36988, 76723, 153865, 308777, 608391, 1189918, 2313136, 4458599, 8562580, 16354499, 31118601, 59018399, 111556847, 210352934, 395641010, 742567333, 1391072247, 2601239676, 4856734666

Offset: 1

Author

R. H. Hardin Feb 16 2012

Keywords

• nonn

Comments

Row 4 of A207269

Examples

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

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +5*a(n-2) -a(n-3) -30*a(n-4) -13*a(n-5) +54*a(n-6) +109*a(n-7) -36*a(n-8) -191*a(n-9) -186*a(n-10) +146*a(n-11) +313*a(n-12) +245*a(n-13) -177*a(n-14) -350*a(n-15) -329*a(n-16) +108*a(n-17) +320*a(n-18) +341*a(n-19) -41*a(n-20) -205*a(n-21) -228*a(n-22) -5*a(n-23) +70*a(n-24) +106*a(n-25) +23*a(n-26) -9*a(n-27) -38*a(n-28) -12*a(n-29) +9*a(n-31) +2*a(n-32) -a(n-34)