OFFSET
1,2
COMMENTS
See reference for more information.
LINKS
I. P. Goulden, J. H. Kwak and J. Lee, Enumerating branched orientable surface coverings over a non-orientable surface, Discr. Math. 303 (2005), 42-55.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Dec 23 2005
STATUS
approved