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

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