A241364 Number of n X 2 0..2 arrays with no element equal to fewer vertical neighbors than horizontal neighbors, with new values 0..2 introduced in row major order.

1, 7, 47, 326, 2284, 16026, 112458, 789166, 5537942, 38862302, 272714782, 1913766030, 13429783278, 94243014094, 661346912462, 4640977825550, 32567892540814, 228543997497870, 1603799162836494, 11254602102332686

Offset

1,2

Links

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

Formula

Empirical: a(n) = 7*a(n-1) + 2*a(n-3) - 8*a(n-4) for n>5.

Empirical g.f.: x*(1 + x)*(1 - x - x^2 - 4*x^3) / ((1 - x)*(1 - 6*x - 6*x^2 - 8*x^3)). - Colin Barker, Oct 30 2018

Example

Some solutions for n=4:
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..0
..1..2....0..1....2..0....0..2....1..1....0..2....0..1....0..0....1..0....0..0
..2..0....1..0....0..0....2..1....1..0....1..0....0..2....2..0....0..1....0..1
..1..2....1..0....0..1....2..1....1..2....1..2....1..0....2..0....0..2....0..2

Crossrefs

Column 2 of A241370.

Sequence in context: A244830 A126528 A214992 * A098405 A104092 A024187

Adjacent sequences: A241361 A241362 A241363 * A241365 A241366 A241367

Keyword

nonn

Author

R. H. Hardin, Apr 20 2014

Status

approved