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A186726 Number of connected regular graphs with n nodes and girth at least 6. 13
1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 6, 1, 33, 1, 386, 1, 7575, 1, 181229, 1, 4624503, 1, 122090549, 1, 3328929974, 1, 93990693868, 26 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,15

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..35.

Jason Kimberley, Connected regular graphs with girth at least 6

Jason Kimberley, Index of sequences counting connected k-regular simple graphs with girth at least g

M. Meringer, Tables of Regular Graphs

FORMULA

a(n) = sum of the n-th row of A186716.

EXAMPLE

a(37) = 13505.

CROSSREFS

Connected regular graphs of any degree with girth at least g: A005177 (g=3), A186724 (g=4), A186725 (g=5), this sequence (g=6), A186727 (g=7), A186728 (g=8), A186729 (g=9).

Connected k-regular simple graphs with girth at least 6: this sequence (any k), A186716 (triangle); specific k: A185116 (k=2), A014374 (k=3), A058348 (k=4).

Sequence in context: A225821 A113766 A204992 * A205405 A112623 A130675

Adjacent sequences:  A186723 A186724 A186725 * A186727 A186728 A186729

KEYWORD

nonn,more,hard

AUTHOR

Jason Kimberley, Nov 23 2011

STATUS

approved

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Last modified April 24 16:26 EDT 2019. Contains 322430 sequences. (Running on oeis4.)