A221823 Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, without consecutive moves in the same direction.

13, 2113, 190756, 18636989, 1804472268, 174820457922, 16936005698353, 1640717334488903, 158947987755078035, 15398437448141904936, 1491757378064714004413, 144517269678468770214198

Offset: 1

Author

R. H. Hardin, Jan 26 2013

Keywords

• nonn

Comments

Column 4 of A221824.

Examples

			Some solutions for n=3
..0..1..0..2....1..0..1..1....0..1..0..1....0..3..0..0....0..0..2..0
..1..4..0..0....2..3..2..0....1..2..0..4....1..1..1..2....2..0..4..0
..0..0..1..3....0..1..1..0....1..2..0..0....0..1..1..2....1..2..1..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..25

Crossrefs

Cf. A221824.