A207565 Number of 4Xn 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 1 1 and 1 1 0 vertically

9, 81, 221, 636, 2234, 6315, 16812, 47596, 129150, 337186, 892181, 2343529, 6046508, 15601217, 40205083, 102833093, 262404045, 669166152, 1701139222, 4316129307, 10943611348, 27709283328, 70072708774, 177098593806, 447280003769

Offset

1,1

Comments

Row 4 of A207564

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -4*a(n-2) +10*a(n-3) -30*a(n-4) +10*a(n-5) -4*a(n-6) +54*a(n-7) +10*a(n-8) -22*a(n-9) -62*a(n-10) -10*a(n-11) +18*a(n-12) +32*a(n-13) +7*a(n-14) -6*a(n-15) -6*a(n-16)

Example

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

Crossrefs

Sequence in context: A207265 A208003 A207881 * A207758 A016946 A144938

Adjacent sequences: A207562 A207563 A207564 * A207566 A207567 A207568

Keyword

nonn

Author

R. H. Hardin Feb 18 2012

Status

approved