A227439 Number of n X 3 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 4 binary array having two adjacent 1's and two adjacent 0's.

8, 62, 457, 3346, 24568, 180575, 1327102, 9752326, 71665377, 526639966, 3870071062, 28439626805, 208991567034, 1535796359850, 11285960160481, 82936058669080, 609464300937756, 4478712154302465, 32912284659166926

Offset

1,1

Comments

Column 3 of A227442.

Links

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

Formula

Empirical: a(n) = 11*a(n-1) -36*a(n-2) +79*a(n-3) -87*a(n-4) -7*a(n-5) +159*a(n-6) -206*a(n-7) +127*a(n-8) -31*a(n-9).

Example

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

Crossrefs

Sequence in context: A198690 A056054 A167251 * A144143 A284225 A229011

Adjacent sequences: A227436 A227437 A227438 * A227440 A227441 A227442

Keyword

nonn

Author

R. H. Hardin Jul 11 2013

Status

approved