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Number of bicolored immersions of unoriented circle into oriented sphere with n double points and no simple loop.
5

%I #11 Jun 09 2024 09:04:09

%S 0,0,2,1,4,9,38,133,640,2864

%N Number of bicolored immersions of unoriented circle into oriented sphere with n double points and no simple loop.

%H Robert Coquereaux and Jean-Bernard Zuber, <a href="https://doi.org/10.1142/S0218216516500474">Maps, immersions and permutations</a>, Journal of Knot Theory and Its Ramifications, Vol. 25, No. 8 (2016), 1650047; <a href="https://arxiv.org/abs/1507.03163">arXiv preprint</a>, arXiv:1507.03163 [math.CO], 2015-2016. See Table 6.

%F a(2*n) = A268568(2*n), a(2*n+1) = 2 * A268569(2*n+1). - _Andrey Zabolotskiy_, Jun 05 2024

%Y Cf. A268561, A268568, A268569, A268573.

%K nonn,more

%O 1,3

%A _N. J. A. Sloane_, Mar 03 2016

%E Name clarified by _Andrey Zabolotskiy_, Jun 08 2024