2,2
S. K. Das, On the enumeration of finite maximal connected topologies, J. Combin. Theory, B 15 (1973), 184-199.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Sequence in context: A173400 A066315 A058499 * A109220 A018034 A000227
Adjacent sequences: A003094 A003095 A003096 * A003098 A003099 A003100
nonn
N. J. A. Sloane (njas(AT)research.att.com).
