A068273 1/6 the number of colorings of an n X n rhombic hexagonal array with 6 colors.

1, 80, 65600, 552093440, 47694893373440, 42294602754348892160, 384991688574716612134952960, 35972520655083241381477879725916160, 34501934082562716587411029908821592862883840, 339679276508747763623945195020701159657032777565470720

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, A212162, A212163.

Extensions

a(7)-a(9) from Alois P. Heinz, May 02 2012

a(10) from Andrew Howroyd, Jun 25 2017