A223180 Rolling icosahedron footprints: number of n X n 0..11 arrays starting with 0 where 0..11 label vertices of an icosahedron and every array movement to a horizontal, vertical or antidiagonal neighbor moves along an icosahedral edge.

1, 20, 400, 14560, 1018720, 141047120, 39288329040, 22231433842560, 25710310945249680, 61010814457361940400

Offset

1,2

Comments

Diagonal of A223186.

Links

Table of n, a(n) for n=1..10.

Example

Some solutions for n=3
..0..7..1....0..5..7....0..1..7....0..1..7....0..2..6....0..7..1....0..7.11
..5..0..7....7..0..1....7..3.11....7..3..1....6..4..2....5..0..7....1..3..7
..7..1..3....1..7..3...11..7..5....1..8..3....2..6..4....7..5.11....7..1..0
Vertex neighbors:
0 -> 1 2 5 6 7
1 -> 0 2 3 7 8
2 -> 0 1 4 6 8
3 -> 1 7 8 9 11
4 -> 2 6 8 9 10
5 -> 0 6 7 10 11
6 -> 0 2 4 5 10
7 -> 0 1 3 5 11
8 -> 1 2 3 4 9
9 -> 3 4 8 10 11
10 -> 4 5 6 9 11
11 -> 3 5 7 9 10

Crossrefs

Cf. A223186.

Sequence in context: A006494 A007545 A055476 * A041181 A041762 A196740

Adjacent sequences: A223177 A223178 A223179 * A223181 A223182 A223183

Keyword

nonn

Author

R. H. Hardin, Mar 18 2013

Status

approved