A122423 Number of unigraphic degree sequences among all graphs (connected or otherwise) on n vertices.

1, 2, 4, 11, 28, 72, 170, 407, 956, 2252

Offset

1,2

Comments

A degree sequence is unigraphic if there is only one graph (up to isomorphism) with that degree sequence.

Links

Table of n, a(n) for n=1..10.

Michael Koren, Pairs of Sequences with a Unique Realization by Bipartite Graphs, Journal of Combinatorial Theory B, 21, 224-234, 1976.

Michael Koren, Sequences with a Unique Realization by Simple Graphs, Journal of Combinatorial Theory B, 21, 234-244, 1976.

Shuo-Yen R Li, Graphic Sequences with Unique Realizations, Journal of Combinatorial Theory B, 19, 42-68, 1975.

Eric Weisstein's World of Mathematics, Unigraphic Graph.

Crossrefs

Cf. A365548 (number of unigraphic graphs on n nodes that are connected).

Cf. A309757 (number of connected graphs that have distinct degree sequences among all connected graphs).

Sequence in context: A024742 A024962 A202085 * A099016 A026122 A108629

Adjacent sequences: A122420 A122421 A122422 * A122424 A122425 A122426

Keyword

nonn,more

Author

Gordon F. Royle, Sep 03 2006

Status

approved