A223280 Rolling icosahedron face footprints: number of nX6 0..19 arrays starting with 0 where 0..19 label faces of an icosahedron and every array movement to a horizontal, diagonal or antidiagonal neighbor moves across an icosahedral edge.
243, 6831, 261819, 10979127, 473368227, 20570223999, 895927195659, 39047604482055, 1702160040384051, 74204651599582287, 3234961829070975771, 141029297731894387287, 6148230806876335875267, 268034791871130540563487
Offset: 1
Keywords
Examples
Some solutions for n=3 ..0..2..3..2..3..2....0..5..0..1..0..1....0..5..0..5..0..5....0..2..0..1..4..1 ..0..2..8..2..8..2....0..5..0..2..0..2....0..5..0..2..0..1....0..2..0..1..0..1 ..8..2..0..2..8.13....0..5..0..2..3..2....7..5..0..2..0..5....0..1..0..1..6..1 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) = 63*a(n-1) -882*a(n-2) +792*a(n-3) +35736*a(n-4) -70768*a(n-5) -246208*a(n-6) +327936*a(n-7) +146432*a(n-8) -180224*a(n-9)
Comments