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 1-8 of 8 results.

A374947 a(n) is the number of suitably connected Legendrian n-Mosaics.

Original entry on oeis.org

1, 2, 20, 1504, 948032, 5204262912, 254112496082944, 111879597850371293184, 448381477417976615986528256, 16469260582635747355818375736459264, 5571666891811926168753521842383673521864704, 17424018517043252553551626372130243982114254609186816
Offset: 1

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Author

Keywords

Comments

A Legendrian n-mosaic is an n X n array of the 10 tiles given in Figure 5 of Pezzimenti and Pandey. These tiles represent part of a Legendrian curve in the front projection.
A Legendrian n-mosaic is suitably connected iff the connection points of each tile coincide with those of all contiguous tiles. Note that the n-mosaic consisting of all blank tiles is vacuously suitably connected even though it does not represent a link.
This is the main diagonal of A375354. It appears to grow at a quadratic exponential rate, and the ratios a(n)/A261400(n) seem to converge to 0 at a quadratic exponential rate.
For more information, see Sections 4 and 5 of Kipe et al. In particular, see Figures 20 and 21 for explicit best-fit models. - Luc Ta, Oct 27 2024

Examples

			For n = 2 there are exactly a(2) = 2 suitably connected Legendrian 2-mosaics, namely the empty mosaic and the Legendrian unknot with maximal Thurston-Bennequin invariant.
		

Crossrefs

Programs

  • Mathematica
    x[0] = o[0] = {{1}};
    x[n_] := ArrayFlatten[{{x[n - 1], o[n - 1]}, {o[n - 1], x[n - 1]}}];
    o[n_] := ArrayFlatten[{{o[n - 1], x[n - 1]}, {x[n - 1], 3*o[n - 1]}}];
    legendrianSquare[n_] := If[n > 1, 2*Total[MatrixPower[x[n - 2] + o[n - 2], n - 2], 2], 1];
    Flatten[ParallelTable[legendrianSquare[n], {n, 1, 11}]] (* This program is adapted from Theorem 1 of Oh, Hong, Lee, and Lee (see Links, cf. A375354). - Luc Ta, Aug 20 2024 *)
  • Rust
    // See Margaret Kipe link

Extensions

a(7)-a(11) from Luc Ta, Aug 20 2024
a(12) from Alois P. Heinz, Aug 20 2024

A375353 T(m,n) = Number of m X n knot/link mosaics read by rows, with 1<=n<=m.

Original entry on oeis.org

1, 1, 2, 1, 4, 22, 1, 8, 130, 2594, 1, 16, 778, 54226, 4183954, 1, 32, 4666, 1144526, 331745962, 101393411126, 1, 64, 27994, 24204022, 26492828950, 31507552821550, 38572794946976686, 1, 128, 167962, 512057546, 2119630825150, 9841277889785426, 47696523856560453790, 234855052870954505606714
Offset: 1

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Author

Luc Ta, Aug 13 2024

Keywords

Comments

An m X n link mosaic is a suitably connected m X n array of the 11 tiles given by Lomonaco and Kauffman. The condition of being suitably connected means that the connection points of each tile coincide with those of the contiguous tiles. Thus, link mosaics depict projections of a link or a knot onto a plane.
The Mathematica program below is based on the algorithm given in Theorem 1 of Oh, Hong, Lee, and Lee.

Examples

			Triangle begins:
  1;
  1,  2;
  1,  4,   22;
  1,  8,  130,    2594;
  1, 16,  778,   54226,   4183954;
  1, 32, 4666, 1144526, 331745962, 101393411126;
  ...
T(2,2) = 2 since the only suitably connected 2 X 2 link mosaics are the empty mosaic and the mosaic depicting an unknot attaining its minimal crossing number.
For all n >= 1, we have T(n,1) = 1 since the only suitably connected mosaic with one column is empty.
		

Crossrefs

The main diagonal T(n,n) is A261400.

Programs

  • Mathematica
    x[0] = o[0] = {{1}};
    x[n_] := ArrayFlatten[{{x[n - 1], o[n - 1]}, {o[n - 1], x[n - 1]}}];
    o[n_] := ArrayFlatten[{{o[n - 1], x[n - 1]}, {x[n - 1], 4*o[n - 1]}}];
    mosaics[m_, n_] := If[m > 1 && n > 1, 2*Total[MatrixPower[x[m - 2] + o[m - 2], n - 2], 2], 1];
    Flatten[ParallelTable[mosaics[m, n], {m, 1, 11}, {n, 1, m}]] (* Luc Ta, Aug 13 2024 *)

Formula

T(m,2) = A000079(m-1) for all m >= 2 and T(m,3) = A261399(m) for all m >= 3 due to Corollary 2 of Hong, H. Lee, H. J. Lee, and Oh.

A375354 T(m,n) is the number of suitably connected m X n Legendrian mosaics read by rows, with 1<=n<=m.

Original entry on oeis.org

1, 1, 2, 1, 4, 20, 1, 8, 104, 1504, 1, 16, 544, 22208, 948032, 1, 32, 2848, 329216, 40930304, 5204262912, 1, 64, 14912, 4883968, 1772261888, 666548862976, 254112496082944, 1, 128, 78080, 72464384, 76795762688, 85575149027328, 97392800416399360, 111879597850371293184
Offset: 1

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Author

Keywords

Comments

An m X n Legendrian mosaic is an m X n array of the 10 tiles given in Figure 5 of Pezzimenti and Pandey. These tiles represent part of a Legendrian curve in the front projection. The condition of being suitably connected means that the connection points of each tile coincide with those of the contiguous tiles.
The Mathematica program below is based on the algorithm given in Theorem 1 of Oh, Hong, Lee, and Lee, adapted to the Legendrian setting: since Legendrian mosaic tiles omit the crossing tile T_9 used in general knot mosaics, the bottom-right submatrix of O_(k+1) is 3*O_k rather than 4*O_k. See Theorem 6 of Kipe et al.
T(m,2) = A375353(m,2) = A000079(m-1) for all m >= 2 since neither classical nor Legendrian link mosaics with only 2 columns or rows can use T_9 tiles.

Examples

			Triangle begins:
  1;
  1,  2;
  1,  4,   20;
  1,  8,  104,   1504;
  1, 16,  544,  22208,   948032;
  1, 32, 2848, 329216, 40930304, 5204262912;
  ...
T(2,2) = 2 since the only suitably connected 2 X 2 Legendrian mosaics are the empty mosaic and the mosaic depicting the Legendrian unknot with maximal Thurston-Bennequin invariant.
For all n >= 1, we have T(n,1) = 1 since the only suitably connected Legendrian mosaic with one column is empty.
		

Crossrefs

The main diagonal T(n,n) is A374947.

Programs

  • Mathematica
    x[0] = o[0] = {{1}};
    x[n_] := ArrayFlatten[{{x[n - 1], o[n - 1]}, {o[n - 1], x[n - 1]}}];
    o[n_] := ArrayFlatten[{{o[n - 1], x[n - 1]}, {x[n - 1], 3*o[n - 1]}}];
    legendrian[m_, n_] := If[m > 1 && n > 1, 2*Total[MatrixPower[x[m - 2] + o[m - 2], n - 2], 2], 1];
    Flatten[ParallelTable[legendrian[m, n], {m, 1, 11}, {n, 1, m}]] (* Luc Ta, Aug 13 2024 *)

Formula

T(m,3) = A082761(m-1) for all m >= 1. - Luc Ta, Aug 20 2024

A375355 T(m, n) is the number of m X n period knot/link mosaics read by rows, with 1 <= n <= m.

Original entry on oeis.org

7, 29, 359, 133, 5519, 316249, 641, 91283, 19946891, 4934695175, 3157, 1549799, 1298065813, 1268810595131, 1300161356831107, 15689, 26576579, 85436799491, 330595705214327, 1353434715973001999, 5644698772550126097593, 78253, 457549079, 5648174618317, 86566215054880187, 1416905739955631598043, 23696846086162116561085541, 399312236302057306354637147077
Offset: 1

Views

Author

Luc Ta, Aug 20 2024

Keywords

Comments

An m X n mosaic is an m X n array of the 11 tiles given by Lomonaco and Kauffman. A period m X n mosaic is an m X n mosaic whose opposite edges are identified. A period mosaic depicts a knot or link 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 2 of Oh, Hong, Lee, Lee, and Yeon.
T(m, n) >= A375356(m, n) for all m and n, with equality iff m = n = 1.
T(m, 1) = A074600(m) for all m. To see this, proceed by induction on m. In Theorem 2 of Oh, Hong, Lee, Lee, and Yeon, it is clear that tr(X_{m+1}) = 2*tr(X_m) and tr(O_{m+1}) = 5*tr(O_m) for all m. The theorem states that T(m+1, 1) = tr(X_{m+1} + O_{m+1}) = tr(X_{m+1}) + tr(O_{m+1}) = 2*tr(X_m) + 5*tr(O_m), and the claim follows since tr(X_1 + O_1) = 7.

Examples

			Triangle begins:
      7;
     29,      359;
    133,     5519,      316249;
    641,    91283,    19946891,      4934695175;
   3157,  1549799,  1298065813,   1268810595131,    1300161356831107;
    ...
T(1,1) = 7 since the only period 1 X 1 link mosaics are given by the tiles T_0 and T_5 through T_10 of Lomonaco and Kauffman.
		

Crossrefs

Programs

  • Mathematica
    x[0] = o[0] = {{1}}; y[0] = p[0] = {{0}};
    x[n_] := ArrayFlatten[{{x[n - 1], p[n - 1]}, {p[n - 1], x[n - 1]}}];
    y[n_] := ArrayFlatten[{{y[n - 1], o[n - 1]}, {o[n - 1], y[n - 1]}}];
    o[n_] := ArrayFlatten[{{o[n - 1], y[n - 1]}, {y[n - 1], 4 * o[n - 1]}}];
    p[n_] := ArrayFlatten[{{p[n - 1], x[n - 1]}, {x[n - 1], 4 * p[n - 1]}}];
    periodcount[m_, n_] := Tr[MatrixPower[x[m] + o[m], n]];
    Flatten[ParallelTable[periodcount[m, n], {m, 1, 11}, {n, 1, m}]]

A375356 T(m, n) is the number of m X n toroidal knot/link mosaics read by rows, with 1 <= n <= m.

Original entry on oeis.org

7, 18, 110, 49, 954, 35237, 171, 11591, 1662837, 308435024, 637, 155310, 86538181, 63440607699, 52006454275147
Offset: 1

Views

Author

Luc Ta, Aug 20 2024

Keywords

Comments

An m X n mosaic is an m X n array of the 11 tiles given by Lomonaco and Kauffman. A period m X n mosaic is an m X n mosaic whose opposite edges are identified. A toroidal m X n mosaic is an equivalence class of period m X n 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 first five rows of the triangle are from Table 2 of Oh, Hong, Lee, Lee, and Yeon.
Clearly, T(m,n) <= A375355(m,n) for all m,n, with equality iff m = n = 1.

Examples

			Triangle begins:
    7;
   18,    110;
   49,    954,    35237;
  171,  11591,  1662837,   308435024;
  637, 155310, 86538181, 63440607699, 52006454275147;
  ...
The only period 1 X 1 link mosaics are given by the tiles T_0 and T_5 through T_10 of Lomonaco and Kauffman. None of these mosaics are cyclic rotations of rows and columns of the others (since there are no rows or columns to permute in the first place). Therefore, T(1,1) = 7.
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

The main diagonal T(n,n) contains A375357 as a subsequence.

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

Views

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}, " "]]

A261399 a(1)=1; thereafter a(n) = (2/5)*(9*6^(n-2)+1).

Original entry on oeis.org

1, 4, 22, 130, 778, 4666, 27994, 167962, 1007770, 6046618, 36279706, 217678234, 1306069402, 7836416410, 47018498458, 282110990746, 1692665944474, 10155995666842, 60935974001050, 365615844006298, 2193695064037786, 13162170384226714, 78973022305360282, 473838133832161690
Offset: 1

Views

Author

N. J. A. Sloane, Aug 19 2015

Keywords

Comments

Partial sums of A081341. - Klaus Purath, Jul 28 2020

Crossrefs

The number 22, the third term here, is the same 22 seen in A261400 and illustrated in a link in that entry.
Cf. A199412.

Formula

G.f.: x-2*x^2*(-2+3*x) / ( (6*x-1)*(x-1) ). - R. J. Mathar, Aug 19 2015
a(n) = 2*A199412(n-2), n>1. - R. J. Mathar, Aug 19 2015
From Klaus Purath, Jul 28 2020: (Start)
a(n) = 7*a(n-1) - 6*a(n-2), n > 2.
a(n) = 6*a(n-1) - 2, n > 1.
a(n) = 3*6^(n-2) + a(n-1), n > 1.
(End)

A376155 Number of prime knots with 10 or fewer crossings whose mosaic number is n.

Original entry on oeis.org

0, 1, 0, 1, 6, 96, 146
Offset: 1

Views

Author

Luc Ta, Sep 12 2024

Keywords

Comments

An n X n mosaic is an n X n array of the 11 tiles given by Lomonaco and Kauffman. The mosaic number of a knot K is the smallest integer n such that K is realizable on an n X n knot mosaic.
Here, we count the unknot as a prime knot.

Examples

			There are exactly 6 prime knots that are realizable on a 5 X 5 knot mosaic but not realizable on a 4 X 4 knot mosaic. Namely, these knots are 4_1, 5_1, 5_2, 6_1, 6_2, and 7_4 (see Table 1 of Lee et al.). Hence, a(5) = 6.
		

Crossrefs

Showing 1-8 of 8 results.