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A032195 Number of necklaces with 10 black beads and n-10 white beads. +0
2
1, 1, 6, 22, 73, 201, 504, 1144, 2438, 4862, 9252, 16796, 29414, 49742, 81752, 130752, 204347, 312455, 468754, 690690, 1001603, 1430715, 2016144, 2804880, 3856892, 5245128, 7060984, 9414328, 12440668, 16301164 (list; graph; listen)
OFFSET

10,3

COMMENT

The g.f. is Z(C_10,x)/x^10, the 10-variate cycle index polynomial for the cyclic group C_10, with substitution x[i]->1/(1-x^i), i=1,...,10. By Polya enumeration, a(n+10) is the number of cyclically inequivalent 10-necklaces whose 10 beads are labeled with nonnegative integers such that the sum of labels is n, for n=0,1,2,... See A102190 for Z(C_10,x). See the comment in A032191 on the equivalence of this problem with the one given in the `Name' line. W. Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Feb 15 2005.

LINKS

C. G. Bower, Transforms (2)

F. Ruskey, Necklaces, Lyndon words, De Bruijn sequences, etc.

Index entries for sequences related to necklaces

FORMULA

"CIK[ 10 ]" (necklace, indistinct, unlabeled, 10 parts) transform of 1, 1, 1, 1...

G.f.: (x^10)*(1-3*x+4*x^2+12*x^3-8*x^4-x^5+31*x^6-4*x^8+16*x^9+11*x^10+3*x^11+8*x^12+4*x^13+4*x^14+x^15+x^16)/((1-x)^4*(1-x^2)^4*(1-x^5)*(1-x^10)).

MATHEMATICA

k = 10; Table[Apply[Plus, Map[EulerPhi[ # ]Binomial[n/#, k/# ] &, Divisors[GCD[n, k]]]]/n, {n, k, 30}] - Robert A. Russell (russell(AT)post.harvard.edu), Sep 27 2004

CROSSREFS

Cf. A004526, A007997, A008610, A008646, A032191, A032192, A032193, A032194.

Sequence in context: A099855 A003469 A027992 this_sequence A111566 A051945 A003699

Adjacent sequences: A032192 A032193 A032194 this_sequence A032196 A032197 A032198

KEYWORD

nonn

AUTHOR

Christian G. Bower (bowerc(AT)usa.net)

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.


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