A254079 Number of primitive (=aperiodic) n-bead necklaces with colored beads of exactly 7 different colors.

720, 17640, 258720, 2963520, 29317680, 263506320, 2215825920, 17758540440, 137337087888, 1033793011440, 7621696948320, 55289495222640, 396017903136240, 2808175618022544, 19754629731587280, 138087381577881960, 960370246763096400, 6652267408747194360

Offset

7,1

Links

Alois P. Heinz, Table of n, a(n) for n = 7..1000

Maple

with(numtheory):
b:= proc(n, k) option remember; `if`(n=0, 1,
      add(mobius(n/d)*k^d, d=divisors(n))/n)
    end:
a:= n-> add(b(n, 7-j)*binomial(7, j)*(-1)^j, j=0..7):
seq(a(n), n=7..30);

Crossrefs

Column k=7 of A254040.

Sequence in context: A056271 A000920 A052779 * A037212 A228909 A126781

Adjacent sequences: A254076 A254077 A254078 * A254080 A254081 A254082

Keyword

nonn

Author

Alois P. Heinz, Jan 25 2015

Status

approved