

A322928


a(0)=1; for n>0, a(n) is the number of rooted 3regular maps with 2n vertices on the projective plane.


0



1, 9, 118, 1773, 28650, 484578, 8457708, 151054173, 2745685954, 50606020854, 943283037684
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OFFSET

0,2


LINKS

Table of n, a(n) for n=0..10.
Evgeniy Krasko, Alexander Omelchenko, Enumeration of rregular maps on the torus. Part I: Rooted maps on the torus, the projective plane and the Klein bottle. Sensed maps on the torus, Discrete Mathematics (2019) Vol. 342, Issue 2, 584599. Also arXiv:1709.03225 [math.CO]. See Th. 3.3 and Table 2.


FORMULA

Theorem 3.3 gives an explicit formula.


CROSSREFS

Sequence in context: A081629 A051617 A166823 * A087984 A197544 A234964
Adjacent sequences: A322925 A322926 A322927 * A322929 A322930 A322931


KEYWORD

nonn,more


AUTHOR

Evgeniy Krasko, Dec 31 2018


EXTENSIONS

Added initial term a(0)=1 to match Taylor series expansion in Theorem 3.3. Deleted incorrect formula and associated Python program.  N. J. A. Sloane, Jan 11 2019


STATUS

approved



