A223479 Rolling icosahedron face footprints: number of nX7 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.

729, 84375, 11374425, 1588785975, 223894186425, 31621425535575, 4468456626780825, 631526586023769975, 89256484380983132025, 12615117535169199386775, 1782968370270784918644825

Offset: 1

Author

R. H. Hardin Mar 20 2013

Keywords

• nonn

Comments

Column 7 of A223480

Examples

			Some solutions for n=3
..0..5..0..5..7.11..7....0..5..0..1..4..1..6....0..5..0..5..0..2..0
..0..5..0..5..7..5..9....0..5..0..1..6..1..0....0..5..0..1..0..2..8
..0..5..9..5..9..5..7....0..1..0..1..0..5..0....0..1..4..1..0..2..0
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
		

Links

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

Formula

Empirical: a(n) = 227*a(n-1) -14764*a(n-2) +411840*a(n-3) -5347200*a(n-4) [phone]*a(n-5) -48000000*a(n-6)