A268573 Number of irreducible indecomposable bicolored immersions of unoriented circle into oriented sphere with n double points.

0, 0, 2, 1, 4, 6, 24, 73, 322, 1274

Offset: 1

Author

N. J. A. Sloane, Mar 03 2016

Keywords

• nonn
• more

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 7.

Crossrefs

Cf. A264760, A264761, A268561, A268572.

Formula

a(2*n) = A264761(2*n), a(2*n+1) = 2 * A264760(2*n+1). - Andrey Zabolotskiy, Jun 05 2024

Extensions

Name clarified by Andrey Zabolotskiy, Jun 08 2024