A186724 - OEIS

A186724

Number of connected regular graphs with n nodes and girth at least 4.

1, 1, 1, 0, 1, 1, 2, 1, 4, 1, 10, 3, 37, 32, 340, 1608, 18020, 193907, 2867725, 32674058, 1581632114, 6705889824

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,7

LINKS

Table of n, a(n) for n=0..21.

Jason Kimberley, Connected regular graphs with girth at least 4

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

FORMULA

a(n) = sum of the n-th row of A186714.

CROSSREFS

Regular graphs, of any degree, with girth at least 4: this sequence (connected), A185214 (disconnected), A185314 (not necessarily connected).

Connected regular graphs of any degree with girth at least g: A005177 (g=3), this sequence (g=4), A186725 (g=5), A186726 (g=6), A186727 (g=7), A186728 (g=8), A186729 (g=9).

Connected k-regular simple graphs with girth at least 4: this sequence (any k), A186714 (triangle); specified degree k: A185114 (k=2), A014371 (k=3), A033886 (k=4), A058275 (k=5), A058276 (k=6), A181153 (k=7), A181154 (k=8), A181170 (k=9).

Sequence in context: A146011 A104620 A243913 * A145930 A145762 A024539

Adjacent sequences: A186721 A186722 A186723 * A186725 A186726 A186727

KEYWORD

nonn,hard,more

AUTHOR

Jason Kimberley, Sep 04 2011

STATUS

approved