1,2

M. A. Sainte-Lagu\"{e}, Les R\'{e}seaux (ou Graphes)}, M\'{e}morial des Sciences Math\'{e}matiques, Fasc. 18, Gauthier-Villars, Paris, 1926, p. 49.

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

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

Sequence in context: A091265 A028415 A035334 this_sequence A063703 A109619 A087228

Adjacent sequences: A002562 A002563 A002564 this_sequence A002566 A002567 A002568

nonn

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