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 1-10 of 10 results.

A242129 Number of tiles added in each step if a centrally symmetric Penrose rhomb tiling, beginning with a central 'Sun' configuration, is successively extended in steps as defined below.

Original entry on oeis.org

5, 5, 10, 15, 20, 25, 40, 30, 30, 45, 60, 55, 65, 55, 70, 75, 90, 75, 90
Offset: 1

Views

Author

Felix Fröhlich, May 05 2014

Keywords

Comments

In each step, add a new tile to each free edge of the current tiling. The first step is the placement of the five central tiles.

Examples

			See illustrations in Fröhlich, 2019.
		

Crossrefs

Cf. A242128 (5-fold, Star), A242888 (7-fold, Star), A242889 (7-fold, Sun), A242890 (8-fold, Star), A242891 (8-fold, Sun), A242892 (9-fold, Star), A242893 (9-fold, Sun), A242894 (Kite and dart, Star), A242895 (Kite and dart, Sun).

Extensions

a(8)-a(19) from Felix Fröhlich, Jun 16 2019

A242128 Beginning with adding a central 'Star' configuration of a centrally symmetric Penrose rhomb tiling as the first step, number of tiles that can be added to the free edges of the current tiling.

Original entry on oeis.org

5, 10, 15, 15, 30, 25, 30, 50, 40, 40, 50, 60, 60, 75, 75
Offset: 1

Views

Author

Felix Fröhlich, May 05 2014

Keywords

Examples

			See illustration in Fröhlich, 2019.
		

Crossrefs

Cf. A242129 (5-fold, Sun), A242888 (7-fold, Star), A242889 (7-fold, Sun), A242890 (8-fold, Star), A242891 (8-fold, Sun), A242892 (9-fold, Star), A242893 (9-fold, Sun), A242894 (Kite and dart, Star), A242895 (Kite and dart, Sun).

Extensions

More terms from Felix Fröhlich, Jun 20 2019

A242888 Beginning with adding a central 'Star' configuration of a centrally symmetric rhomb tiling with 7-fold symmetry, number of tiles that can be added to the free edges of the tiling.

Original entry on oeis.org

7, 14, 21, 14, 14, 28
Offset: 1

Views

Author

Felix Fröhlich, May 25 2014

Keywords

Crossrefs

A242894 Beginning with a central 'Star' configuration of a Penrose 'Kite' and 'Dart' tiling with rotational symmetry as the first step, number of tiles that can be added to the free edges of the current tiling.

Original entry on oeis.org

5, 10, 10, 20, 20, 25, 35, 40, 40, 45, 45
Offset: 1

Views

Author

Felix Fröhlich, May 25 2014

Keywords

Comments

The initial 5 corresponds to the initial "star" made from 5 "darts". Given the 5-fold symmetry, all terms are divisible by 5. See the illustration for the first 8 terms. - M. F. Hasler, Jun 04 2019

Crossrefs

A242895 Beginning with a central 'Sun' configuration of a Penrose 'Kite' and 'Dart' tiling with rotational symmetry as the first step, number of tiles that can be added to the free edges of the current tiling.

Original entry on oeis.org

5, 5, 10, 15, 20, 25, 30
Offset: 1

Views

Author

Felix Fröhlich, May 25 2014

Keywords

Comments

The initial 5 corresponds to the "Sun" configuration made of 5 Penrose "Kites". In view of the 5-fold rotational symmetry, all terms are divisible by 5, see the illustrations given as LINKS. - M. F. Hasler, Jun 05 2019

Crossrefs

A242890 Beginning with a central 'Star' configuration of a centrally symmetric arrangement of 8 rhombi with 8-fold rotational symmetry, number of tiles that can be added to the free edges of the tiling.

Original entry on oeis.org

8, 16, 16, 16, 16, 16, 24
Offset: 1

Views

Author

Felix Fröhlich, May 25 2014

Keywords

Crossrefs

A242891 Beginning with a centrally symmetric 'Sun' configuration of 8 rhombi with rotational symmetry, number of tiles that can be added to the free edges of the tiling.

Original entry on oeis.org

8, 8, 8, 16, 24, 24, 40, 32, 48, 48, 40
Offset: 1

Views

Author

Felix Fröhlich, May 25 2014

Keywords

Crossrefs

A242892 Beginning with a centrally symmetric 'Star' configuration of 9 rhombi with rotational symmetry, number of tiles that can be added to the free edges of the tiling.

Original entry on oeis.org

9, 9, 18, 27, 27, 18
Offset: 1

Views

Author

Felix Fröhlich, May 25 2014

Keywords

Crossrefs

A242893 Beginning with a centrally symmetric 'Sun' configuration of 9 rhombi with rotational symmetry, number of tiles that can be added to the free edges of the tiling.

Original entry on oeis.org

9, 9, 9, 9, 18, 27, 27, 36
Offset: 1

Views

Author

Felix Fröhlich, May 25 2014

Keywords

Crossrefs

A309118 Number of tiles added at iteration n when successively, layer by layer, building a symmetric patch of a rhombille tiling around a central star of six rhombs.

Original entry on oeis.org

6, 6, 12, 18, 24, 24, 36, 30, 48, 36, 60, 42, 72, 48, 84, 54, 96, 60, 108, 66, 120, 72, 132, 78, 144, 84, 156, 90, 168, 96, 180, 102, 192, 108, 204, 114, 216, 120, 228, 126, 240, 132, 252, 138, 264, 144, 276, 150, 288, 156, 300, 162, 312, 168, 324, 174, 336
Offset: 1

Views

Author

Felix Fröhlich, Jul 13 2019

Keywords

Examples

			See illustration in Fröhlich, 2019.
		

Crossrefs

Cf. A242128 (5-fold, Star), A242129 (5-fold, Sun), A242888 (7-fold, Star), A242889 (7-fold, Sun), A242890 (8-fold, Star), A242891 (8-fold, Sun), A242892 (9-fold, Star), A242893 (9-fold, Sun), A242894 (Kite and dart, Star), A242895 (Kite and dart, Sun).

Programs

  • Magma
    I:=[6,6,12,18,24,24]; [n le 6 select I[n] else 2*Self(n-2)-Self(n-4): n in [1..60]]; // Vincenzo Librandi, Jul 16 2019
  • Mathematica
    Join[{6, 6}, LinearRecurrence[{0, 2, 0, -1}, {12, 18, 24, 24}, 60]] (* Vincenzo Librandi, Jul 16 2019 *)
  • PARI
    a(n) = if(n<3, 6, if(n%2==0, 6*((n+2)/2), 12*((n-1)/2)))
    
  • PARI
    Vec(6*x*(1 + x + x^3 + x^4 - x^5) / ((1 - x)^2*(1 + x)^2) + O(x^40)) \\ Colin Barker, Jul 13 2019
    

Formula

a(2*n+1) = A008594(n).
a(2*n) = A008588(n+1) for n > 1.
From Colin Barker, Jul 13 2019: (Start)
G.f.: 6*x*(1 + x + x^3 + x^4 - x^5) / ((1 - x)^2*(1 + x)^2).
a(n) = 2*a(n-2) - a(n-4) for n>6.
(End)
Showing 1-10 of 10 results.