A222556 Number of (n+2)X1 arrays of occupancy after each element moves up to +-n places but not 0

2, 20, 102, 427, 1668, 6372, 24230, 92279, 352596

Offset

1,1

Comments

Row 2 of A222555

Links

Table of n, a(n) for n=1..9.

Example

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

Crossrefs

Sequence in context: A356344 A220856 A035599 * A103101 A267678 A009357

Adjacent sequences: A222553 A222554 A222555 * A222557 A222558 A222559

Keyword

nonn

Author

R. H. Hardin Feb 24 2013

Status

approved