2,1

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

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: A051536 A043013 A145544 this_sequence A123520 A012847 A128721

Adjacent sequences: A006299 A006300 A006301 this_sequence A006303 A006304 A006305

nonn

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