A185136 Number of not necessarily connected 3-regular simple graphs on 2n vertices with girth exactly 6.

0, 0, 0, 0, 0, 0, 0, 1, 1, 5, 32, 385, 7573, 181224, 4624481, 122089999, 3328899592, 93988909792

Offset

0,10

Links

Table of n, a(n) for n=0..17.

Jason Kimberley, Index of sequences counting not necessarily connected k-regular simple graphs with girth exactly g

Formula

a(n) = A006926(n) + A185036(n).

Crossrefs

Not necessarily connected 3-regular simple graphs on 2n vertices with girth exactly g: A185130 (triangle); fixed g: A185133 (g=3), A185134 (g=4), A185135 (g=5), this sequence (g=6).

Sequence in context: A094653 A135250 A006926 * A014374 A185336 A125709

Adjacent sequences: A185133 A185134 A185135 * A185137 A185138 A185139

Keyword

nonn,hard,more

Author

Jason Kimberley, Mar 21 2012

Status

approved