A223397 4X4 square grid graph coloring a rectangular array: number of nX3 0..15 arrays where 0..15 label nodes of the square grid graph and every array movement to a horizontal or vertical neighbor moves along an edge of this graph

152, 2360, 39480, 672784, 11561512, 199425400, 3445747472, 59582558136, 1030635314552, 17830297764560, 308491144480488, 5337532888545800, 92351643563233552, 1597906958454938296, 27647738113504778888

Offset

1,1

Comments

Column 3 of A223402

Links

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

Formula

Empirical: a(n) = 18*a(n-1) +69*a(n-2) -1554*a(n-3) +2085*a(n-4) +10353*a(n-5) -18959*a(n-6) -11633*a(n-7) +31508*a(n-8) -5302*a(n-9) -10390*a(n-10) +4408*a(n-11) -440*a(n-12) for n>13

Example

Some solutions for n=3
..5..1..2....5..4..5....3..7..6....6.10.14....5..9.10....7..6..5...10..9..8
..6..2..3....6..5..1....7.11.10...10.14.10....6..5..6...11.10..9....9.10..9
..5..1..2....2..1..2...11.10.14....6.10..6....2..1..5....7..6.10...10.11.10
Vertex neighbors:
0 -> 1 4
1 -> 0 2 5
2 -> 1 3 6
3 -> 2 7
4 -> 0 5 8
5 -> 4 1 6 9
6 -> 5 2 7 10
7 -> 6 3 11
8 -> 4 9 12
9 -> 8 5 10 13
10 -> 9 6 11 14
11 -> 10 7 15
12 -> 8 13
13 -> 12 9 14
14 -> 13 10 15
15 -> 14 11

Crossrefs

Sequence in context: A208485 A364815 A359447 * A239065 A229418 A035823

Adjacent sequences: A223394 A223395 A223396 * A223398 A223399 A223400

Keyword

nonn

Author

R. H. Hardin Mar 19 2013

Status

approved