1,5
Table of n, a(n) for n=1..9.
Gordon Royle, Small Graphs: Class 2 Graphs.
Eric Weisstein's World of Mathematics, Class 2 Graph
a(n) = A001349(n) - A099436(n). - Andrew Howroyd, Sep 03 2019
Cf. A001349 (number of connected graphs on n nodes).
Cf. A099437 (number of simple class-2 graphs on n nodes).
Cf. A099436 (number of connected class-1 graphs on n nodes).
Sequence in context: A127138 A064081 A211364 * A002178 A013558 A161000
Adjacent sequences: A099435 A099436 A099437 * A099439 A099440 A099441
nonn,more
Eric W. Weisstein, Oct 15 2004
approved
