1,2

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

F. Harary and R. W. Robinson, Labeled bipartite blocks, Canad. J. Math., 31 (1979), 60-68.

Sequence in context: A039515 A037302 A157591 this_sequence A062226 A110717 A068988

Adjacent sequences: A005333 A005334 A005335 this_sequence A005337 A005338 A005339

nonn

N. J. A. Sloane (njas(AT)research.att.com).