A221605 Number of n X 4 arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, without move-in move-out left turns.

4, 53, 811, 12270, 184193, 2764070, 41480899, 622510123, 9342086217, 140197824897, 2103965848896, 31574471975014, 473841949757344, 7111003899609738, 106715702327136893, 1601495553082204043

Offset

1,1

Comments

Column 4 of A221609.

Links

Table of n, a(n) for n=1..16.

Example

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

Crossrefs

Cf. A221609.

Sequence in context: A241872 A109801 A099340 * A307172 A275801 A158259

Adjacent sequences: A221602 A221603 A221604 * A221606 A221607 A221608

Keyword

nonn

Author

R. H. Hardin, Jan 20 2013

Status

approved