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A008980 Number of immersions of the oriented circle into the oriented plane with n double points. 6
2, 3, 10, 39, 204, 1262, 8984, 67959, 544504, 4535030, 39004772, 344217402, 3103896536 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
REFERENCES
V. I. Arnold, Topological Invariants of Plane Curves and Caustics, American Math. Soc., 1994, p. 16.
LINKS
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.
S. M. Gusein-Zade and F. S. Duzhin, Enumeration of plane curves with up to 10 selfintersections, Pascal program and result table, 05 Apr 1998.
PROG
(Pascal) Cf. link.
CROSSREFS
Sequence in context: A144720 A164933 A003048 * A064183 A050381 A129716
KEYWORD
nonn,nice,more
AUTHOR
EXTENSIONS
Additional comments from Sergei Duzhin, Nov 11 2000
a(11)-a(12) from Sean A. Irvine, Apr 19 2018
STATUS
approved

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Last modified June 20 05:29 EDT 2024. Contains 373512 sequences. (Running on oeis4.)