A184146 1/4 the number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock having at least two equal elements connected horizontally or vertically.

499, 17203, 584143, 19882711, 676507975, 23019453235, 783273204631, 26652142523719, 906882231446575, 30858134866789795, 1049997948625823743, 35727878490908505943, 1215698852533977865783, 41366119750324063746547

Offset

1,1

Comments

Column 2 of A184153.

Links

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

Formula

Empirical: a(n) = 33*a(n-1) + 53*a(n-2) - 637*a(n-3) + 756*a(n-4).

Empirical g.f.: x*(499 + 736*x - 10003*x^2 + 12096*x^3) / (1 - 33*x - 53*x^2 + 637*x^3 - 756*x^4). - Colin Barker, Apr 12 2018

Example

Some solutions for 5 X 3 with a(1,1)=0:
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0
..0..2..0....0..0..0....0..0..0....0..0..0....0..3..0....0..2..0....0..0..0
..2..2..1....2..0..2....3..0..3....3..0..1....2..2..2....1..1..0....0..0..2
..0..0..1....1..1..1....3..0..2....3..3..3....3..3..3....3..0..0....1..1..1
..1..0..3....2..2..2....2..0..2....1..2..2....1..0..2....2..2..1....3..1..1

Crossrefs

Cf. A184153.

Sequence in context: A230004 A203735 A093945 * A214191 A132475 A220024

Adjacent sequences: A184143 A184144 A184145 * A184147 A184148 A184149

Keyword

nonn

Author

R. H. Hardin, Jan 09 2011

Status

approved