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A112849 Number of congruence classes (epimorphisms/vertex partitionings induced by graph endomorphisms) of undirected cycles of even length: |C(C_2n)|. +0
2
1, 4, 11, 36, 127, 463, 1717, 6436, 24311, 92379, 352717, 1352079, 5200301, 20058301 (list; graph; listen)
OFFSET

1,2

REFERENCES

M. A. Michels, About The Structure of Graph Endomorphisms, Diploma thesis, University of Oldenburg, Germany, 2005

M. A. Michels and U. Knauer, The congruence classes of paths and cycles, Discrete Math., 309 (2009), 5352-5359. [From N. J. A. Sloane, Sep 15 2009]

FORMULA

|C(C_2n)| = 1 + (1/2)*binomial(2n-1, n-1) + (1/2)*binomial(2n-1, n)

CROSSREFS

Cf. A112850.

Sequence in context: A149241 A149242 A149243 this_sequence A149244 A149245 A054105

Adjacent sequences: A112846 A112847 A112848 this_sequence A112850 A112851 A112852

KEYWORD

easy,nonn,more

AUTHOR

Martin Alexander Michels (martinmichels(AT)t-online.de), Sep 24 2005

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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