OFFSET
1,4
COMMENTS
LINKS
Alois P. Heinz, Rows n = 1..8, flattened
Wikipedia, Chromatic Polynomial
EXAMPLE
3 example graphs: o--o--o
. | /|\ |
. |/ | \|
. o--o o--o--o
. | /| | /|\ |
. |/ | |/ | \|
. o o--o o--o--o
Graph: SH_(1,1) SH_(2,2) SH_(3,3)
Vertices: 1 4 9
Edges: 0 5 16
The staggered hexagonal square grid graph SH_(2,2) has chromatic polynomial q^4 -5*q^3 +8*q^2 -4*q => row 2 = [1, -5, 8, -4, 0].
Triangle T(n,k) begins:
1, 0;
1, -5, 8, -4, 0;
1, -16, 112, -448, 1120, -1791, ...
1, -33, 510, -4898, 32703, -160859, ...
1, -56, 1508, -25992, 321994, -3051871, ... , -3101089710, ...
1, -85, 3520, -94620, 1855860, -28306676, ...
1, -120, 7068, -272344, 7720110, -171656543, ...
1, -161, 12782, -667058, 25738055, -783003395, ...
CROSSREFS
KEYWORD
sign,tabf
AUTHOR
Alois P. Heinz, May 03 2012
STATUS
approved