1,3

a(3)=4: the four disconnected covers are {{1},{2,3}}, {{2},{1,3}}, {{3},{1,2}} and {{1},{2},{3}}.

Cf. A048143, A006126, A007153.

Sequence in context: A118792 A137341 A163885 this_sequence A064050 A162128 A119926

Adjacent sequences: A120335 A120336 A120337 this_sequence A120339 A120340 A120341

nonn

Greg Huber (huber(AT)alum.mit.edu), Jun 22 2006