A128237 Number of n-node (unlabeled) graphs with girth 4.

0, 1, 3, 15, 59, 296, 1604, 11303, 102108, 1250114, 20738069, 467523871, 14230096759, 581439661069, 31720637440030

Offset

3,3

Links

Table of n, a(n) for n=3..17.

Formula

a(n) = A006785(n) - A006787(n).

Crossrefs

Cf. A006785, A006787.

Cf. A128041, A128042, A128236-A128243.

Sequence in context: A069009 A328104 A179604 * A176311 A036750 A286183

Adjacent sequences: A128234 A128235 A128236 * A128238 A128239 A128240

Keyword

nonn

Author

Keith Briggs, May 05 2007

Extensions

Corrected and extended by Martin Fuller, May 01 2015

Status

approved