cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A048952 Prime 2-component links with n crossings.

Original entry on oeis.org

0, 1, 0, 1, 1, 3, 8, 16, 61, 185, 638, 2818, 11292
Offset: 1

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Author

Keywords

References

  • D. Rolfsen, Knots and Links. Wilmington, DE: Publish or Perish Press, 1976.
  • D. J. A. Welsh, On the number of knots and links, Sets, Graphs and Numbers (Budapest, 1991) 713-718, Colloq. Math. Soc. Janos Bolyai, 60, North-Holland, Amsterdam, 1992.

Crossrefs

Extensions

More terms from Steven Finch, Aug 02 2003
a(12)-a(13) from Faullin added by Andrey Zabolotskiy, Feb 26 2023

A049344 Prime unoriented alternating links (not necessarily connected knots) with n crossings.

Original entry on oeis.org

0, 1, 1, 2, 3, 8, 14, 39, 96, 297, 915, 3308, 12417, 51347, 222595, 1016975, 4799520, 23301779, 115405815, 581071711, 2963793396, 15283327150, 79544488072, 417377448058
Offset: 1

Views

Author

N. J. A. Sloane, Feb 10 2001

Keywords

Crossrefs

Cf. A002864, A086771. Row sums of A059739.

Extensions

a(20)-a(24) from Bruce Fontaine's table (produced by him together with Stuart Rankin and Ortho Flint in 2007) added by Andrey Zabolotskiy, Jun 08 2022

A086826 Number of nonsplittable links (prime or composite) with n crossings.

Original entry on oeis.org

1, 0, 1, 1, 3, 4, 15, 24, 82
Offset: 0

Views

Author

Steven Finch, Aug 07 2003

Keywords

Comments

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.

Examples

			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.
		

Crossrefs

Extensions

a(7) and a(8) from Stéphane Legendre, Jan 06 2014

A087071 Number of distinct prime 4-component links with crossing number n.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 3, 1, 25, 39, 307, 1161
Offset: 1

Views

Author

Steven Finch and Eric W. Weisstein, Aug 07 2003

Keywords

Crossrefs

Extensions

a(10) corrected, a(12)-a(13) from Faullin added by Andrey Zabolotskiy, Feb 27 2023
Showing 1-4 of 4 results.