A183995 Number of (n+1) X 2 0..2 arrays with all 2 X 2 subblock sums the same.

81, 171, 361, 855, 2025, 5175, 13225, 35535, 95481, 265431, 737881, 2100255, 5978025, 17298375, 50055625, 146516175, 428862681, 1265299191, 3733087801, 11073888255, 32849750025, 97806145575, 291205933225, 869194951215

Offset

1,1

Comments

Column 1 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.: x*(81 - 315*x - 665*x^2 + 3549*x^3 + 270*x^4 - 12000*x^5 + 6300*x^6 + 12420*x^7 - 9720*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 3 X 2:
..0..1....1..1....0..1....2..1....0..1....0..2....2..1....2..1....2..0....2..0
..0..0....0..1....1..1....1..2....2..0....0..2....2..1....2..1....0..2....0..1
..1..0....2..0....1..0....2..1....1..0....0..2....2..1....1..2....2..0....2..0

Crossrefs

Cf. A184003.

Sequence in context: A232923 A250655 A184003 * A044413 A044794 A350198

Adjacent sequences: A183992 A183993 A183994 * A183996 A183997 A183998

Keyword

nonn

Author

R. H. Hardin, Jan 08 2011

Status

approved