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Search: id:A086825
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| A086825 |
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Number of knots (prime or composite) with n crossings. |
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+0
3
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OFFSET
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0,6
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LINKS
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S. R. Finch, Knots, links and tangles
Eric Weisstein's World of Mathematics, Knot
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EXAMPLE
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a(7)=8 since we have 7 prime knots and one composite knot (the connected sum 3_1#4_1 of the trefoil knot 3_1 and the figure eight knot 4_1). Note that 3_1*#4_1=3_1#4_1, where * denotes mirror image because 4_1 is achiral. a(8)=25 since we have 21 prime knots and four composites (3_1#5_1, 3_1#5_2, 3_1*#5_1 and 3_1*#5_2).
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CROSSREFS
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Cf. A002863.
Sequence in context: A092097 A088144 A100501 this_sequence A093365 A128600 A066846
Adjacent sequences: A086822 A086823 A086824 this_sequence A086826 A086827 A086828
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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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