2,2

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

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

Theory of graphs: International Symposium. Held at the International Computation Center in Rome, Jul, 1966. Scientific editor, P. Rosenstiehl; Gordon and Breach, New York; Dunod, Paris 1967, xviii+416 pp. See page 238.

Sequence in context: A012110 A054739 A117508 this_sequence A016449 A161377 A122495

Adjacent sequences: A001136 A001137 A001138 this_sequence A001140 A001141 A001142

nonn

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