A068252 1/24 the number of colorings of a 5 X 5 octagonal array with n colors.

15, 13544240, 138446293905, 122914516488960, 25999554922206250, 2153128175383358880, 92188903926678792030, 2420834781123276840960, 43619102772258066624945, 582825001391348708850000, 6107144216640392108077895, 52317129545418639168933120

Offset: 4

Author

R. H. Hardin, Feb 24 2002

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 4..1000
• Alois P. Heinz, Formula for A068252

Crossrefs

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

Programs

Maple

a:= n-> (749775400182+ (-5612178463551+ (20061456442182+ (-45672704671212+ (74464103614803+ (-92636079268387+ (91447345270476+ (-73522860568402+ (49016457219873+ (-27440963053418+ (13013052032729+ (-5257328793792+
(1815373485182+ (-536334824998+ (135430280705+ (-29134045002+ (5309217327+ (-812594023+ (103170636+ (-10676360+ (877812+ (-55183+ (2492+(-72+n)*n) *n)*n) *n)*n) *n)*n) *n)*n) *n)*n) *n)*n) *n)*n) *n) *n) *n) *n) *n) *n) *n) *n) *n/24:
seq(a(n), n=4..20); #  Alois P. Heinz, May 04 2012

Extensions

Extended beyond a(9) by Alois P. Heinz, May 04 2012