3,1

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).

Hugo Schiff, Zur Statistik chemischer Verbindungen, Berichte der Deutschen Chemischen Gesellschaft, Vol. 8, pp. 1542-1547, 1875.

Sequence in context: A018356 A026383 A162963 this_sequence A115725 A079572 A053391

Adjacent sequences: A002091 A002092 A002093 this_sequence A002095 A002096 A002097

nonn

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