A068296 1/7 the number of colorings of an n X n octagonal array with 7 colors.

1, 120, 161280, 2451486720, 421421199390720, 819296954885530030080, 18013654371239090908333148160, 4479149596637688119857975807616194560, 12595676735919821000208123310178819903753287680, 400570738126155220679966449710339235598075113573822617600

Offset: 1

Author

R. H. Hardin, Feb 24 2002

Keywords

• nonn

Crossrefs

Cf. A068239-A068305, A000332, A002417, A027441, A212208, A212209.

Extensions

a(6)-a(8) from Alois P. Heinz, May 04 2012

a(9)-a(10) from Andrew Howroyd, Jun 25 2017