A183794 1/4 the number of (n+1) X 2 0..3 arrays with no 2 X 2 subblock having sum 6.

53, 706, 9395, 125050, 1664363, 22152262, 294840155, 3924240130, 52230527579, 695173613662, 9252564864971, 123149031156442, 1639078901387051, 21815678294545462, 290360530538406779, 3864616839260883250

Offset

1,1

Comments

Column 1 of A183802.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) + 81*a(n-2) + 206*a(n-3) + 144*a(n-4).

Empirical g.f.: x*(53 + 388*x + 866*x^2 + 576*x^3) / (1 - 6*x - 81*x^2 - 206*x^3 - 144*x^4). - Colin Barker, Apr 04 2018

Example

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

Crossrefs

Cf. A183802.

Sequence in context: A142780 A289808 A183802 * A201153 A077794 A200532

Adjacent sequences: A183791 A183792 A183793 * A183795 A183796 A183797

Keyword

nonn

Author

R. H. Hardin, Jan 07 2011

Status

approved