6,3

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).

A. J. W. Duijvestijn and P. J. Federico, The number of polyhedral (3-connected planar) graphs. Math. Comp. 37 (1981), no. 156, 523-532.

Handbook of Combinatorics, North-Holland '95, p. 892. (Gives different last term)

W. T. Tutte, A new branch of enumerative graph theory, Bull. Amer. Math. Soc., 68 (1962), 500-504.

W. T. Tutte, A census of planar maps, Canad. J. Math., 15 (1963), 249-271.

Cf. A000256.

Sequence in context: A034458 A067001 A057343 this_sequence A032087 A165164 A136591

Adjacent sequences: A000284 A000285 A000286 this_sequence A000288 A000289 A000290

nonn,nice

N. J. A. Sloane (njas(AT)research.att.com), Simon Plouffe (simon.plouffe(AT)gmail.com)