A223398 4X4 square grid graph coloring a rectangular array: number of nX4 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

488, 17280, 672784, 26836512, 1080643264, 43699580872, 1770698081072, 71817607508112, 2914205675816528, 118279017948229984, 4801123318150081688, 194895185405773535816, 7911713694335733918224, 321177747138973784749952

Offset

1,1

Comments

Column 4 of A223402

Links

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

Formula

Empirical: a(n) = 68*a(n-1) -1109*a(n-2) -4869*a(n-3) +222894*a(n-4) -1156279*a(n-5) -5574138*a(n-6) +59890884*a(n-7) -52622076*a(n-8) -826607085*a(n-9) +2286714099*a(n-10) +2497011383*a(n-11) -15386990735*a(n-12) +5944839703*a(n-13) +37858988026*a(n-14) -34983660849*a(n-15) -41038690128*a(n-16) +56013716567*a(n-17) +17383507922*a(n-18) -41048181688*a(n-19) +1451420401*a(n-20) +14584600251*a(n-21) -3405796689*a(n-22) -2205179649*a(n-23) +919592697*a(n-24) +43558091*a(n-25) -72404073*a(n-26) +12563140*a(n-27) -685336*a(n-28) for n>29

Example

Some solutions for n=3
..8..4..5..9....4..5..6..5....8..9..8.12....5..4..8..9....8..9..8..4
..4..5..4..8....8..9..5..9...12..8..4..8....4..5..9..5....4..8..9..8
..8..9..8.12...12.13..9.10....8..9..8..4....8..9..5..6....8.12..8.12
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: A253336 A205315 A118449 * A214334 A201835 A201215

Adjacent sequences: A223395 A223396 A223397 * A223399 A223400 A223401

Keyword

nonn

Author

R. H. Hardin Mar 19 2013

Status

approved