A223203 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 vertical neighbor moves across an icosahedral edge

1, 15, 657, 90111, 39868737, 57728430255, 275769851453745, 4367470887097715487, 230051556728875753924449, 40390820217552511124819066703

Offset

1,2

Comments

Diagonal of A223209

Links

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

Example

Some solutions for n=3
..0..2..0....0..5..7....0..5..0....0..5..0....0..5..7....0..2..0....0..1..6
..1..0..2....5..0..5....2..0..5....5..0..5....5..7.11....2..3..2....1..0..1
..0..5..0....0..5..9....0..2..0....0..5..7....7.11.12....8..2..3....6..1..6
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: A092958 A222268 A280179 * A279465 A349889 A279531

Adjacent sequences: A223200 A223201 A223202 * A223204 A223205 A223206

Keyword

nonn

Author

R. H. Hardin Mar 18 2013

Status

approved