0,4

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

a(3) = 3 since the three connected graphs with three edges are a path, a triangle and a "Y".

The first difference between this sequence and A002905 is for n=9 edges where we see K_{3,3}, the "utility graph".

Cf. A002905, A066951.

Adjacent sequences: A046088 A046089 A046090 this_sequence A046092 A046093 A046094

Sequence in context: A005913 A056690 A066951 this_sequence A002905 A087610 A156436

nonn,nice,hard

Brendan McKay (bdm(AT)cs.anu.edu.au)