0,2

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).

F. Harary and E. M. Palmer, Enumeration of self-converse digraphs, Mathematika, 13 (1966), 151-157.

F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 155, Table 6.6.1.

Equals A029849*2 - A000595. Cf. A002499.

Sequence in context: A123307 A126101 A157994 this_sequence A002833 A139015 A139678

Adjacent sequences: A002497 A002498 A002499 this_sequence A002501 A002502 A002503

nonn,nice,easy

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

In the Encyclopedia of Integer Sequences the n=6 term is given incorrectly as 484256.

Corrected and extended with formula by Christian G. Bower (bowerc(AT)usa.net) Jun 15 1998.