A183996 Number of (n+1) X 3 0..2 arrays with all 2 X 2 subblock sums the same.

171, 309, 579, 1233, 2691, 6417, 15555, 40041, 104211, 282609, 771699, 2167353, 6111171, 17563617, 50584035, 147570921, 430968051, 1269505809, 3741492819, 11090690073, 32883337251, 97873303617, 291340216515, 869463485001

Offset

1,1

Comments

Column 2 of A184003.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 6*a(n-1) - 60*a(n-3) + 85*a(n-4) + 150*a(n-5) - 360*a(n-6) + 396*a(n-8) - 216*a(n-9).

Empirical g.f.: 3*x*(57 - 239*x - 425*x^2 + 2673*x^3 - 234*x^4 - 8968*x^5 + 5676*x^6 + 9252*x^7 - 7992*x^8) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)). - Colin Barker, Apr 09 2018

Example

Some solutions for 4 X 3:
..1..2..1....0..2..0....2..0..2....0..2..0....1..2..2....0..2..1....2..0..1
..0..1..0....1..0..1....2..1..2....0..2..0....1..2..0....1..2..0....1..2..2
..1..2..1....1..1..1....1..1..1....0..2..0....1..2..2....1..1..2....2..0..1
..1..0..1....1..0..1....1..2..1....0..2..0....1..2..0....2..1..1....1..2..2

Crossrefs

Cf. A184003.

Sequence in context: A349097 A120819 A115078 * A062907 A266315 A116459

Adjacent sequences: A183993 A183994 A183995 * A183997 A183998 A183999

Keyword

nonn

Author

R. H. Hardin, Jan 08 2011

Status

approved