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Search: id:A086826
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| A086826 |
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Number of nonsplittable links (prime or composite) with n crossings. |
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+0
1
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OFFSET
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0,5
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COMMENT
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A link L is splittable if we can embed a plane in R^3, disjoint from L, that separates one or more components of L from other components of L. Otherwise L is nonsplittable.
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LINKS
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S. R. Finch, Knots, links and tangles
Eric Weisstein's World of Mathematics, Splittable Link
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EXAMPLE
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a(5)=4 since we have 2 prime knots, as well as the Whitehead link; and the trefoil knot linked with a circle.
a(6)=15 since we have 3 prime knots, as well as 2 composite knots (the square & granny knots); 6 prime links; a chain of four circles simply-intertwined; four circles simply-intertwined in the shape of a "T"; three circles, two doubly-intertwined and two simply-intertwined; and the figure-eight knot linked with a circle.
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CROSSREFS
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Cf. A086771.
Sequence in context: A006074 A081714 A117718 this_sequence A130409 A157351 A071167
Adjacent sequences: A086823 A086824 A086825 this_sequence A086827 A086828 A086829
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KEYWORD
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nonn
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AUTHOR
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S. R. Finch (Steven.Finch(AT)inria.fr), Aug 07 2003
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