A221484 Number of 2 X n arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, without consecutive moves in the same direction.

0, 4, 8, 73, 292, 1713, 8235, 43733, 220672, 1142790, 5840082, 30047605, 154064032, 791329272, 4060908537, 20849136414, 107016685715, 549372170263, 2820041046796, 14476302849381, 74310986678816, 381462539353767

Offset

1,2

Comments

Row 2 of A221483.

Links

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

Formula

Empirical: a(n) = a(n-1) + 17*a(n-2) + 22*a(n-3) + a(n-4) - 14*a(n-5) - 2*a(n-6) + a(n-7).

Empirical g.f.: x^2*(1 - x)*(4 + 8*x + 5*x^2) / ((1 + 3*x + x^2)*(1 - 4*x - 6*x^2 + 5*x^4 - x^5)). - Colin Barker, Aug 06 2018

Example

Some solutions for n=3:
..1..1..1....0..1..1....1..2..1....0..3..1....0..3..0....0..2..0....1..2..0
..0..3..0....1..3..0....0..2..0....1..1..0....1..1..1....1..2..1....0..2..1

Crossrefs

Cf. A221483.

Sequence in context: A274461 A206346 A240503 * A338314 A288956 A353032

Adjacent sequences: A221481 A221482 A221483 * A221485 A221486 A221487

Keyword

nonn

Author

R. H. Hardin, Jan 17 2013

Status

approved