

A186725


Number of connected regular graphs with n nodes and girth at least 5.


13



1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 2, 1, 3, 1, 10, 1, 50, 1, 456, 2, 5786, 9, 91070, 3918, 1744339, 4131992, 163639193, 4018022150, 119026595851
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OFFSET

0,11


LINKS

Table of n, a(n) for n=0..28.
Jason Kimberley, Connected regular graphs with girth at least 5
Jason Kimberley, Index of sequences counting connected kregular simple graphs with girth at least g
M. Meringer, Tables of Regular Graphs
M. Meringer, Fast generation of regular graphs and construction of cages, J. Graph Theory 30 (2) (1999) 137146. [Jason Kimberley, Jan 29 2011]


FORMULA

a(n) = sum of the nth row of A186715.


CROSSREFS

Connected regular graphs of any degree with girth at least g: A005177 (g=3), A186724 (g=4), this sequence (g=5), A186726 (g=6), A186727 (g=7), A186728 (g=8), A186729 (g=9).
Connected kregular simple graphs with girth at least 5: this sequence (all k), A186715 (triangle); A185115 (k=2), A014372 (k=3), A058343 (k=4), A205295 (k=5).
Sequence in context: A198315 A126761 A090559 * A301935 A237978 A098570
Adjacent sequences: A186722 A186723 A186724 * A186726 A186727 A186728


KEYWORD

nonn,hard,more


AUTHOR

Jason Kimberley, Oct 17 2011


EXTENSIONS

a(26) corrected by the author, due to A186715(26,3) being corrected, May 19 2017


STATUS

approved



