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A008988
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Number of immersions of oriented circle into unoriented sphere with n double points.
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9
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1, 1, 2, 6, 21, 97, 579, 3812, 27328, 206410, 1625916, 13241177, 110859326, 950069179, 8307012899, 73908363060, 667683905600
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OFFSET
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0,3
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COMMENTS
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a(10) = 1625916 by sampling method (to be confirmed, cf. ref. arXiv:1507.03163). - Robert Coquereaux, Nov 23 2015
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REFERENCES
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V. I. Arnold, Topological Invariants of Plane Curves and Caustics, American Math. Soc., 1994, p. 18.
Guy Valette, A Classification of Spherical Curves Based on Gauss Diagrams, Arnold Math J. (2016) 2:383-405, DOI 10.1007/s40598-016-0049-3.
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PROG
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CROSSREFS
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KEYWORD
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nonn,nice,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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