A223476 Rolling icosahedron face footprints: number of n X n 0..19 arrays starting with 0 where 0..19 label faces of an icosahedron and every array movement to a horizontal or antidiagonal neighbor moves across an icosahedral edge

1, 27, 2025, 421875, 288507825, 622332801675, 4468456626780825, 104443823338086658275, 8163685522687864520397825, 2101858460730043160691131026875

Offset

1,2

Comments

Diagonal of A223480

Links

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

Example

Some solutions for n=3
..0..1..0....0..2..8....0..2..8....0..2..8....0..2..8....0..2..8....0..2..8
..0..5..7....8..9.14....0..2..3....0..2..8....0..2..0....3..2..8....8..2..3
..7..5..9...14.11..7....3..4.17....8..2..8....3..2..0....3..2..3....3..4..3
Face neighbors:
0 -> 1 2 5
1 -> 0 4 6
2 -> 0 3 8
3 -> 2 4 16
4 -> 3 1 17
5 -> 0 7 9
6 -> 1 7 10
7 -> 6 5 11
8 -> 2 9 13
9 -> 8 5 14
10 -> 6 12 17
11 -> 7 12 14
12 -> 11 10 19
13 -> 8 15 16
14 -> 9 11 15
15 -> 14 13 19
16 -> 3 13 18
17 -> 4 10 18
18 -> 16 17 19
19 -> 15 18 12

Crossrefs

Sequence in context: A211926 A304119 A017199 * A013779 A075081 A017307

Adjacent sequences: A223473 A223474 A223475 * A223477 A223478 A223479

Keyword

nonn

Author

R. H. Hardin Mar 20 2013

Status

approved