A268566 Number of chiral immersions of oriented circle into oriented sphere with 2n double points.

0, 1, 16, 564, 27231, 1625324, 110854838, 8306977585, 667683610221

Offset

0,3

Links

Table of n, a(n) for n=0..8.

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 Eq. (17), s_m.

Formula

a(n) = A008986(2*n) - A008988(2*n). - Andrey Zabolotskiy, Jun 05 2024

Crossrefs

Cf. A008986, A008987, A268565.

Sequence in context: A131515 A223106 A268564 * A189147 A063082 A223197

Adjacent sequences: A268563 A268564 A268565 * A268567 A268568 A268569

Keyword

nonn,more

Author

N. J. A. Sloane, Mar 03 2016

Extensions

Name clarified and a(0), a(6)-a(8) added using formula by Andrey Zabolotskiy, Jun 08 2024

Status

approved