A001431 Number of graphs with n nodes and n-3 edges.

0, 0, 1, 1, 2, 5, 10, 24, 63, 165, 467, 1405, 4435, 14775, 51814, 190443, 732472, 2939612, 12277230, 53233295, 239083372, 1109921554, 5316143531, 26225625392, 133050795412, 693227353094, 3704785464812, 20285853687809, 113690627637475, 651559904414667

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy

References

• J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 146.
• N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Sean A. Irvine, Table of n, a(n) for n = 1..40
• 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.

Programs

Mathematica

(* first do *) Needs["Combinatorica`"] (* then *) Table[ NumberOfGraphs[n, n-3], {n, 3, 27}] (* Robert G. Wilson v *)

Extensions

More terms from Vladeta Jovovic, Jan 12 2000