2,2

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

Andresen, E.; Kjeldsen, K.; On certain subgraphs of a complete transitively directed graph. Discrete Math. 14 (1976), no. 2, 103-119.

Sequence in context: A145166 A113079 A138427 this_sequence A003084 A010573 A043083

Adjacent sequences: A005327 A005328 A005329 this_sequence A005331 A005332 A005333

nonn

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