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A268572
Number of bicolored immersions of unoriented circle into oriented sphere with n double points and no simple loop.
5
0, 0, 2, 1, 4, 9, 38, 133, 640, 2864
OFFSET
1,3
LINKS
Robert Coquereaux and Jean-Bernard Zuber, Maps, immersions and permutations, Journal of Knot Theory and Its Ramifications, Vol. 25, No. 8 (2016), 1650047; arXiv preprint, arXiv:1507.03163 [math.CO], 2015-2016. See Table 6.
FORMULA
a(2*n) = A268568(2*n), a(2*n+1) = 2 * A268569(2*n+1). - Andrey Zabolotskiy, Jun 05 2024
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Mar 03 2016
EXTENSIONS
Name clarified by Andrey Zabolotskiy, Jun 08 2024
STATUS
approved