A189247 Number of n X 2 array permutations with each element making zero or one king moves

2, 24, 152, 1168, 8448, 62272, 456320, 3350016, 24579584, 180376576, 1323614208, 9712930816, 71274930176, 523026923520, 3838053810176, 28164247060480, 206673697308672, 1516604287614976, 11129082140426240, 81666965136998400

Offset

1,1

Comments

Column 2 of A189254.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) + 12*a(n-2) - 16*a(n-3).

Empirical g.f.: 2*x*(1 + 6*x - 8*x^2) / (1 - 6*x - 12*x^2 + 16*x^3). - Colin Barker, Mar 01 2018

Example

Some solutions for 3 X 2:
..1..2....1..2....1..2....3..1....0..1....1..0....0..2....2..0....2..1....0..1
..0..3....0..4....3..0....5..0....4..2....3..2....3..1....5..1....3..0....3..5
..5..4....5..3....4..5....4..2....3..5....5..4....4..5....4..3....4..5....2..4

Crossrefs

Cf. A189254.

Sequence in context: A264566 A163752 A035600 * A234352 A241623 A288443

Adjacent sequences: A189244 A189245 A189246 * A189248 A189249 A189250

Keyword

nonn

Author

R. H. Hardin, Apr 19 2011

Status

approved