0,3

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

Tutte, W. T.; On the enumeration of planar maps. Bull. Amer. Math. Soc. 74 1968 64-74.

T. R. S. Walsh, Combinatorial Enumeration of Non-Planar Maps. Ph.D. Dissertation, Univ. of Toronto, 1971.

T. R. S. Walsh and A. B. Lehman, Counting rooted maps by genus, J. Comb. Thy B13 (1972), 122-141 and 192-218.

Sequence in context: A028561 A009638 A121942 this_sequence A129437 A048252 A066866

Adjacent sequences: A006291 A006292 A006293 this_sequence A006295 A006296 A006297

nonn

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