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: A112895 A157585 A045645 this_sequence A057121 A039515 A037302

Adjacent sequences: A005332 A005333 A005334 this_sequence A005336 A005337 A005338

nonn

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