1,3

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

R. W. Robinson, personal communication.

R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1979.

R. W. Robinson, Table of n, a(n) for n = 1..22

Sequence in context: A060150 A103461 A101563 this_sequence A083452 A081461 A110698

Adjacent sequences: A007130 A007131 A007132 this_sequence A007134 A007135 A007136

nonn

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