A068295 1/6 the number of colorings of an n X n octagonal array with 6 colors.

1, 60, 21060, 44172540, 553785175620, 41503847098683420, 18595665812583520041060, 49808667823922052573513153300, 797553247913411612275102392386088300, 76343133584713932892876357250654965547341140, 43684986787209742051887297631700585399912369700067860

Offset: 1

Author

R. H. Hardin, Feb 24 2002

Keywords

• nonn

Crossrefs

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

Extensions

a(7)-a(8) from Alois P. Heinz, May 04 2012

a(9)-a(11) from Andrew Howroyd, Jun 25 2017