0,2

The old entry with this sequence number was a duplicate of A007875.

John H. Conway, Heiko Dietrich and E. A. O'Brien, Counting groups: gnus, moas and other exotica.

Cf. A000001, A072410.

Sequence in context: A009838 A088335 A066318 this_sequence A135249 A110365 A047892

Adjacent sequences: A066949 A066950 A066951 this_sequence A066953 A066954 A066955

nonn,more

N. J. A. Sloane (njas(AT)research.att.com), Oct 03 2008

a(5) may be 720.