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A165628 Number of 7-regular graphs (septic graphs) on 2n vertices. 11
1, 0, 0, 0, 1, 5, 1547, 21609301, 733351105935 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

COMMENTS

Because the triangle A051031 is symmetric, a(n) is also the number of (2n-8)-regular graphs on 2n vertices.

REFERENCES

M. Meringer, Fast Generation of Regular Graphs and Construction of Cages. Journal of Graph Theory, 30 (1999), 137-146.

LINKS

Table of n, a(n) for n=0..8.

Jason Kimberley, Index of sequences counting not necessarily connected k-regular simple graphs with girth at least g

M. Meringer, Tables of Regular Graphs

N. J. A. Sloane, Transforms

FORMULA

Euler transformation of A014377.

CROSSREFS

7-regular simple graphs: A014377 (connected), A165877 (disconnected), this sequence (not necessarily connected).

Regular graphs A005176 (any degree), A051031 (triangular array), chosen degrees: A000012 (k=0), A059841 (k=1), A008483 (k=2), A005638 (k=3), A033301 (k=4), A165626 (k=5), A165627 (k=6), this sequence (k=7), A180260 (k=8).

Sequence in context: A184973 A184971 A014377 * A119747 A177906 A127106

Adjacent sequences:  A165625 A165626 A165627 * A165629 A165630 A165631

KEYWORD

nonn,hard,more

AUTHOR

Jason Kimberley, Sep 22 2009

EXTENSIONS

Cross-references edited by the author, Nov 07 2009 and Oct 17 2011

STATUS

approved

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Last modified December 6 00:38 EST 2016. Contains 278771 sequences.