0,3

F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Camb. 1998, p. 307.

Cf. A058928.

Sequence in context: A127091 A063429 A007406 this_sequence A083224 A093188 A155629

Adjacent sequences: A058924 A058925 A058926 this_sequence A058928 A058929 A058930

nonn,frac,easy,more

N. J. A. Sloane (njas(AT)research.att.com), Jan 12 2001