A207786 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 0 and 1 0 1 vertically

9, 81, 253, 791, 2173, 5241, 12567, 28101, 61397, 131083, 272789, 560651, 1133751, 2266643, 4487109, 8799557, 17130019, 33113221, 63623053, 121586791, 231212705, 437760595, 825496887, 1550995293, 2904417145, 5422206945, 10094193051

Offset

1,1

Comments

Row 4 of A207785

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -13*a(n-3) -6*a(n-4) +41*a(n-5) +10*a(n-6) -57*a(n-7) -32*a(n-8) +66*a(n-9) +18*a(n-10) -31*a(n-11) +14*a(n-13) -30*a(n-14) +4*a(n-15) +32*a(n-16) -13*a(n-17) -12*a(n-18) +a(n-19) +6*a(n-20) -9*a(n-21) +12*a(n-22) -2*a(n-23) -3*a(n-25) +2*a(n-26) -2*a(n-27) +a(n-28)

Example

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

Crossrefs

Sequence in context: A207415 A207020 A207364 * A223189 A207781 A207165

Adjacent sequences: A207783 A207784 A207785 * A207787 A207788 A207789

Keyword

nonn

Author

R. H. Hardin Feb 20 2012

Status

approved