A223206 Rolling icosahedron face footprints: number of nX5 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

81, 1875, 50553, 1412907, 39868737, 1127761923, 31921015497, 903661481115, 25583075832465, 724276345970163, 20504869741550745, 580510427181846027, 16434750355138945761, 465281963351360897763, 13172534004090254190441

Offset

1,1

Comments

Column 5 of A223209

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 31*a(n-1) -24*a(n-2) -1612*a(n-3) +3816*a(n-4) +1152*a(n-5) -2784*a(n-6) +256*a(n-7)

Example

Some solutions for n=3
..0..1..4..3..4....0..2..0..2..0....0..1..0..2..3....0..2..0..1..6
..1..4..3..4..1....2..8..2..0..2....5..0..5..0..2....1..0..1..4..1
..4..1..4..1..6....8..2..3..2..3....0..2..0..5..0....0..1..4..1..4
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: A205910 A236811 A206669 * A296650 A233371 A225019

Adjacent sequences: A223203 A223204 A223205 * A223207 A223208 A223209

Keyword

nonn

Author

R. H. Hardin Mar 18 2013

Status

approved