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A268561
Number of bicolored immersions of unoriented circle into oriented sphere with n double points.
3
1, 2, 3, 12, 37, 198, 1143, 7658, 54559, 413086, 3251240, 26484550, 221714164, 1900156948, 16613990484, 147816887598, 1335367515821
OFFSET
0,2
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 2, Table 5, and Table 9, line UOc.
FORMULA
a(2*n) = A008986(2*n), a(2*n+1) = 2 * A008987(2*n+1). - Andrey Zabolotskiy, Jun 05 2024
CROSSREFS
Sequence in context: A353831 A107240 A099171 * A352099 A012307 A012311
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Mar 02 2016
EXTENSIONS
Name clarified and a(0), a(11)-a(16) added using formula by Andrey Zabolotskiy, Jun 08 2024
STATUS
approved