A186747 Number of connected regular simple graphs on n vertices with girth exactly 7.

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 3, 0, 21, 0, 545, 0, 30368, 0, 1782839, 0, 95079080, 0, 4686063107, 0

Offset: 0

Author

Jason Kimberley, Apr 03 2012

Keywords

• nonn
• more
• hard

Links

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

Formula

a(n) = A186727(n) - A186728(n).