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A008985 Triangle T(n,k) giving number of immersions of the oriented circle into the oriented plane with n double points and index k. 6
1, 1, 1, 1, 1, 2, 3, 3, 2, 4, 10, 11, 10, 4, 10, 35, 57, 57, 35, 10, 26, 133, 290, 364, 290, 133, 26 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,6

REFERENCES

V. I. Arnold, Topological Invariants of Plane Curves and Caustics, American Math. Soc., 1994, p. 18.

LINKS

Table of n, a(n) for n=0..26.

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, A008983, A008984, A054993.

Sequence in context: A309076 A073078 A034799 * A326699 A138652 A323833

Adjacent sequences:  A008982 A008983 A008984 * A008986 A008987 A008988

KEYWORD

nonn,nice,tabl,more

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified June 4 17:14 EDT 2020. Contains 334828 sequences. (Running on oeis4.)