A186743 Number of connected regular simple graphs on n vertices with girth exactly 3.

0, 0, 0, 1, 1, 1, 3, 3, 13, 21, 157, 536, 18942, 389404, 50314456, 2942196832, 1698517018391

Offset: 0

Author

Jason Kimberley, Dec 01 2011

Keywords

• nonn
• more
• hard

Links

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

Crossrefs

Connected k-regular simple graphs with girth exactly 3: this sequence (any k), A186733 (triangular array); specified k: A006923 (k=3),A184943 (k=4), A184953 (k=5), A184963 (k=6), A184973 (k=7),A184983 (k=8), A184993 (k=9).

Formula

a(n) = A005177(n) - A186724(n).