2,1

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

R. C. Read, Some Enumeration Problems in Graph Theory. Ph.D. Dissertation, Department of Mathematics, Univ. London, 1958.

Adjacent sequences: A006709 A006710 A006711 this_sequence A006713 A006714 A006715

Sequence in context: A080295 A084108 A006713 this_sequence A099057 A123278 A127605

nonn

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