A048180 Number of graphs with n nodes and n+2 edges.

1, 4, 24, 131, 663, 3252, 15772, 75415, 359307, 1711908, 8191607, 39500169, 192525021, 950868860, 4769060224, 24331970791, 126457607026, 670143402073, 3623530476832, 19998343352758, 112668088476243, 647904733883526

Offset

4,2

References

J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 146.

Links

Sean A. Irvine, Table of n, a(n) for n = 4..36

M. L. Stein and P. R. Stein, Enumeration of Linear Graphs and Connected Linear Graphs up to p = 18 Points. Report LA-3775, Los Alamos Scientific Laboratory of the University of California, Los Alamos, NM, Oct 1967

Crossrefs

Cf. A008406.

Sequence in context: A174443 A180222 A192070 * A057391 A071079 A153337

Adjacent sequences: A048177 A048178 A048179 * A048181 A048182 A048183

Keyword

nonn,easy

Author

N. J. A. Sloane

Extensions

More terms from Vladeta Jovovic, Jan 03 2000

More terms from Sean A. Irvine, Jun 07 2017

Status

approved