A068292 1/18 times the number of colorings of an n X n staggered hexagonal array with 18 colors.

1, 4352, 4294971392, 961201829493850112, 48781126844255370222607142912, 561399464545957024370182236743498291167232, 1465126373454769055363011684465705776628549543645731295232, 867083863998912174882104147806181674429733314821142479758142332970286825472

Offset: 1

Author

R. H. Hardin, Feb 24 2002

Keywords

• nonn

Comments

Terms for rhombic- and staggered- hexagonal arrays are the same for n in 1..4.

Crossrefs

Cf. A068239-A068305, A000332, A002417, A027441, A212194, A212195.

Extensions

a(5)-a(8) from Alois P. Heinz, May 03 2012