A240888 Number of n X 3 0..2 arrays with no element equal to a different number of vertical neighbors than horizontal neighbors, with new values 0..2 introduced in row major order.

2, 11, 57, 289, 1485, 7609, 38981, 199761, 1023597, 5245049, 26876501, 137719297, 705694973, 3616090505, 18529407461, 94947553233, 486525966349, 2493034391385, 12774694280053, 65459511713057, 335424674724381, 1718767975363881

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 8*a(n-2) + 14*a(n-3) + 4*a(n-4).

Empirical g.f.: x*(2 + 5*x + 8*x^2 + 2*x^3) / (1 - 3*x - 8*x^2 - 14*x^3 - 4*x^4). - Colin Barker, Oct 29 2018

Example

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

Crossrefs

Column 3 of A240893.

Sequence in context: A332524 A037490 A037570 * A120464 A164581 A054130

Adjacent sequences: A240885 A240886 A240887 * A240889 A240890 A240891

Keyword

nonn

Author

R. H. Hardin, Apr 14 2014

Status

approved