Table of n, a(n) for n=1..4.
a(3) = 5 as (P1 + K1)*K1 + K1 has 5 vertices and is easily seen minimal for 3. Here P1 is the path with one edge and K1 is an isolated vertex.
Sequence in context: A073695 A268694 A068825 * A019730 A198838 A089103
Adjacent sequences: A097908 A097909 A097910 * A097912 A097913 A097914
Dan Schwarz (dan_schwarz(AT)hotmail.com), Sep 04 2004