0,2

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

Walsh, T. R. S.; Generating nonisomorphic maps without storing them. SIAM J. Algebraic Discrete Methods 4 (1983), no. 2, 161-178.

T. R. S. Walsh, personal communication.

Wormald, Nicholas C. Counting unrooted planar maps. Discrete Math. 36 (1981), no. 2, 205-225.

V. A. Liskovets, A reductive technique for enumerating nonisomorphic planar maps, Discr. Math., v.156 (1996), 197-217.

Cf. A090376.

Sequence in context: A003500 A129876 A038055 this_sequence A131180 A047990 A000939

Adjacent sequences: A006382 A006383 A006384 this_sequence A006386 A006387 A006388

nonn,nice

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