login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A008983 Number of immersions of the unoriented circle into the unoriented plane with n double points. 7
1, 2, 5, 20, 82, 435, 2645, 18489, 141326, 1153052, 9819315, 86305315, 776868505 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

V. I. Arnold, Topological Invariants of Plane Curves and Caustics, American Math. Soc., 1994, p. 16.

LINKS

Table of n, a(n) for n=0..12.

S. R. Finch, Knots, links and tangles

S. R. Finch, Knots, links and tangles, Aug 08 2003. [Cached copy, with permission of the author]

S. M. Gusein-Zade and F. S. Duzhin, On the number of topological types of plane curves; (Russian) Uspekhi Mat. Nauk 53 (1998), no. 3(321), 197-198. English translation: Russian Mathematical Surveys 53 (1998) 626-627.

CROSSREFS

Cf. A008980, A008981, A008982, A008984, A008985, A054993.

Sequence in context: A186767 A009737 A280624 * A286284 A286285 A192101

Adjacent sequences:  A008980 A008981 A008982 * A008984 A008985 A008986

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane

EXTENSIONS

Additional comments from Sergei Duzhin, Nov 11 2000

a(11)-a(12) from Sean A. Irvine, Apr 19 2018

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 2 18:09 EDT 2020. Contains 334787 sequences. (Running on oeis4.)