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.

A375357 a(n) is the number of p X p toroidal knot/link mosaics, where p = A000040(n).

Original entry on oeis.org

110, 35237, 52006454275147, 8149229312286883803155895853, 101957128471911748968541302399445156486848984449235985038696169948167385
Offset: 1

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Author

Luc Ta, Aug 20 2024

Keywords

Comments

A p X p mosaic is an p X p array of the 11 tiles given by Lomonaco and Kauffman. A period p X p mosaic is an p X p mosaic whose opposite edges are identified. A toroidal p X p mosaic is an equivalence class of period p X p mosaics up to finite sequences of cyclic rotations of rows and columns. A toroidal mosaic depicts the projection of a knot or link on the surface of a torus iff the connection points of each tile coincide with those of the contiguous tiles and with those of the tiles on identified edges.
The Mathematica program below is based on the algorithm given in Theorem 4 of Oh, Hong, Lee, Lee, and Yeon.

Examples

			An exhaustive list of all 110 distinct 2 X 2 toroidal link mosaics is given collectively by Appendix A of Carlisle and Laufer and Figure 4 of Oh, Hong, Lee, Lee, and Yeon.
		

Crossrefs

This is a subsequence of the diagonal of A375356.

Programs

  • Mathematica
    <A375355","Data"], PolygonalNumber[q], 2] - 2*Sum[f[q, k], {k, 0, (q - 1)/2}];
    toroidalcount[q_] := If[q > 2, (1/q^2) * g[q] + (2/q) * Sum[f[q, k], {k, 0, (q - 1)/2}] + 7, 110]
    Monitor[Table[toroidalcount[Prime[n]], {n, 1, 5}], Row[{ProgressIndicator[n, {1, 5}], n}, " "]]