OFFSET

1,3

LINKS

Omar Sehlouli, Marko Riedel, Hexagon coloring

Marko Riedel, Image of the five colorings of the hexagon (n=3).

FORMULA

For n>=2, (1/2)(n-1)! + (1/(2n)) * Sum_{p=0..n} C(n,p) ((-1)^p/2^(n-p)) ((2n-p)! + p(2n-p-1)!).

EXAMPLE

When n=2 the coloring of the nodes of the square with two instances each of black and white must alternate and a rotation by Pi/4 takes one coloring to the other, so there is just one coloring.

CROSSREFS

KEYWORD

nonn

AUTHOR

Marko Riedel, Mar 31 2017

STATUS

approved