1,2
See reference for more information.
Table of n, a(n) for n=1..3.
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.
Sequence in context: A120660 A110720 A200822 * A305057 A333633 A222355
Adjacent sequences: A112610 A112611 A112612 * A112614 A112615 A112616
nonn,bref
N. J. A. Sloane, Dec 23 2005
approved
