A186745 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A186745

Number of connected regular simple graphs on n vertices with girth exactly 5.

1

0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 2, 0, 8, 0, 48, 0, 450, 1, 5753, 8, 90684, 3917, 1736764, 4131991, 163457964, 4018022149, 119021971348

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

OFFSET

0,13

LINKS

Table of n, a(n) for n=0..28.

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

FORMULA

a(n) = A186725(n) - A186726(n).

CROSSREFS

Sequence in context: A347596 A211163 A239275 * A109573 A305809 A349139

Adjacent sequences: A186742 A186743 A186744 * A186746 A186747 A186748

KEYWORD

nonn,more,hard

AUTHOR

Jason Kimberley, Apr 03 2012

EXTENSIONS

a(26) corrected by the author, due to correction of A186725, May 19 2017

STATUS

approved