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.

Previous Showing 61-70 of 6133 results. Next

A315462 Coordination sequence Gal.6.339.6 where Gal.u.t.v denotes the coordination sequence for a vertex of type v in tiling number t in the Galebach list of u-uniform tilings.

Original entry on oeis.org

1, 6, 11, 16, 21, 25, 30, 35, 39, 44, 49, 54, 60, 66, 71, 76, 81, 85, 90, 95, 99, 104, 109, 114, 120, 126, 131, 136, 141, 145, 150, 155, 159, 164, 169, 174, 180, 186, 191, 196, 201, 205, 210, 215, 219, 224, 229, 234, 240, 246
Offset: 0

Views

Author

Brian Galebach and N. J. A. Sloane, Jun 18 2018

Keywords

Comments

Note that there may be other vertices in the Galebach list of u-uniform tilings with u <= 6 that have this same coordination sequence. See the Galebach link for the complete list of A-numbers for all these tilings.

Formula

From Chai Wah Wu, Dec 20 2019: (Start)
a(n) = 2*a(n-1) - a(n-2) - a(n-4) + 2*a(n-5) - a(n-6) - a(n-8) + 2*a(n-9) - a(n-10) for n > 10 (conjectured).
G.f.: (x^10 + 4*x^9 + x^6 + 3*x^5 + x^4 + 4*x + 1)/(x^8*(x - 1)^2 + x^4*(x - 1)^2 + (x - 1)^2) (conjectured). (End)

A315464 Coordination sequence Gal.6.346.5 where Gal.u.t.v denotes the coordination sequence for a vertex of type v in tiling number t in the Galebach list of u-uniform tilings.

Original entry on oeis.org

1, 6, 11, 16, 21, 25, 31, 35, 40, 45, 50, 56, 62, 67, 72, 77, 81, 87, 91, 96, 101, 106, 112, 118, 123, 128, 133, 137, 143, 147, 152, 157, 162, 168, 174, 179, 184, 189, 193, 199, 203, 208, 213, 218, 224, 230, 235, 240, 245, 249
Offset: 0

Views

Author

Brian Galebach and N. J. A. Sloane, Jun 18 2018

Keywords

Comments

Note that there may be other vertices in the Galebach list of u-uniform tilings with u <= 6 that have this same coordination sequence. See the Galebach link for the complete list of A-numbers for all these tilings.

Formula

From Chai Wah Wu, Dec 20 2019: (Start)
a(n) = a(n-1) + a(n-11) - a(n-12) for n > 12 (conjectured).
G.f.: (x^12 + 5*x^11 + 5*x^10 + 5*x^9 + 5*x^8 + 4*x^7 + 6*x^6 + 4*x^5 + 5*x^4 + 5*x^3 + 5*x^2 + 5*x + 1)/(x^12 - x^11 - x + 1) (conjectured). (End)

A316319 Coordination sequence for a trivalent node in a chamfered version of the 3^6 triangular tiling of the plane.

Original entry on oeis.org

1, 3, 7, 14, 25, 38, 51, 63, 75, 87, 99, 111, 123, 135, 147, 159, 171, 183, 195, 207, 219, 231, 243, 255, 267, 279, 291, 303, 315, 327, 339, 351, 363, 375, 387, 399, 411, 423, 435, 447, 459, 471, 483, 495, 507, 519, 531, 543, 555, 567, 579, 591, 603, 615, 627, 639
Offset: 0

Views

Author

Rémy Sigrist and N. J. A. Sloane, Jul 01 2018

Keywords

Comments

Let E denote the lattice of Eisenstein integers u + v*w in the plane, with each point joined to its six neighbors. Here u and v are ordinary integers and w = (-1+sqrt(-3))/2 is a complex cube root of unity. Let theta = w - w^2 = sqrt(-3). Then theta*E is a sublattice of E of index 3 (Conway-Sloane, Fig. 7.2). The tiling considered in this sequence is obtained by replacing each node in theta*E by a small hexagon.

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, 3rd. ed., 1993. See Fig. 7.2, page 199.

Crossrefs

See A316320 for hexavalent node.
See A250120 for links to thousands of other coordination sequences.
Cf. A017557.

Programs

  • PARI
    Vec((1 + x + x^2)*(1 + x^2 + 2*x^3 + x^4 - x^5) / (1 - x)^2 + O(x^50)) \\ Colin Barker, Mar 11 2020

Formula

a(n) = 12*n-21 = A017557(n-2) for n > 5.
From Colin Barker, Mar 11 2020: (Start)
G.f.: (1 + x + x^2)*(1 + x^2 + 2*x^3 + x^4 - x^5) / (1 - x)^2.
a(n) = 2*a(n-1) - a(n-2) for n>7.
(End)

Extensions

Terms a(16) and beyond from Andrey Zabolotskiy, Sep 30 2019

A316320 Coordination sequence for a hexavalent node in a chamfered version of the 3^6 triangular tiling of the plane.

Original entry on oeis.org

1, 6, 15, 27, 39, 51, 63, 75, 87, 99, 111, 123, 135, 147, 159, 171, 183, 195, 207, 219, 231, 243, 255, 267, 279, 291, 303, 315, 327, 339, 351, 363, 375, 387, 399, 411, 423, 435, 447, 459, 471, 483, 495, 507, 519, 531, 543, 555, 567, 579, 591, 603, 615, 627, 639
Offset: 0

Views

Author

Rémy Sigrist and N. J. A. Sloane, Jul 01 2018

Keywords

Comments

Let E denote the lattice of Eisenstein integers u + v*w in the plane, with each point joined to its six neighbors. Here u and v are ordinary integers and w = (-1+sqrt(-3))/2 is a complex cube root of unity. Let theta = w - w^2 = sqrt(-3). Then theta*E is a sublattice of E of index 3 (Conway-Sloane, Fig. 7.2). The tiling considered in this sequence is obtained by replacing each node in theta*E by a small hexagon.

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, 3rd. ed., 1993. See Fig. 7.2, page 199.

Crossrefs

See A316319 for trivalent node.
See A250120 for links to thousands of other coordination sequences.

Programs

  • PARI
    Vec((1 + 3*x)*(1 + x + x^2) / (1 - x)^2 + O(x^50)) \\ Colin Barker, Mar 11 2020

Formula

a(n) = 12*n-9 = A017557(n-1) for n > 1.
From Colin Barker, Mar 11 2020: (Start)
G.f.: (1 + 3*x)*(1 + x + x^2) / (1 - x)^2.
a(n) = 2*a(n-1) - a(n-2) for n>3.
(End)

Extensions

Terms a(15) and beyond from Andrey Zabolotskiy, Sep 30 2019

A342285 Coordination sequence with respect to the central vertex of a dodecagon-based tiling of the plane by copies of a certain Goldberg quadrilateral tile.

Original entry on oeis.org

1, 6, 6, 18, 30, 36, 42, 54, 60, 66, 72, 78, 84, 90, 102, 108, 114, 120, 126, 132, 138, 144, 150, 156, 162, 168, 174, 180, 186, 198, 204, 210, 216, 222, 228, 234, 240, 246, 252, 258, 264, 270, 276, 282, 288, 294, 300, 306, 312, 318, 324, 330, 336, 342, 348, 354, 360
Offset: 0

Views

Author

N. J. A. Sloane, Mar 23 2021

Keywords

Comments

There are many ways to tile the plane with the Goldberg tile; this is a particularly symmetric one.
In Cye Waldman's drawing, six copies of the gray sector are placed at the degree-4 vertices of the decagon, and 6 copies of a similar sector at the degree-6 vertices of the decagon.

References

  • Goldberg, M. (1955). “Central Tessellations,” Scripta Mathematica, 21, pp. 253-260. See Fig.7b.
  • Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987; Fig. 1.3.6(a), page 30.

Crossrefs

Programs

  • PARI
    See Links section.

Formula

Apparently, a(n) = 6*A138591(n-1) for n > 1. - Rémy Sigrist, Mar 30 2021

Extensions

More terms from Rémy Sigrist, Mar 29 2021

A242941 a(n) is the number of convex uniform tessellations in dimension n.

Original entry on oeis.org

1, 11, 28, 143
Offset: 1

Views

Author

Felix Fröhlich, May 27 2014

Keywords

Comments

Terms for n > 4 have not been determined so far. Alfredo Andreini in 1905 gave a value of 25 for a(3), later found to be incorrect. The value 28 for a(3) was given by Norman Johnson in 1991 and later in 1994 independently by Branko Grünbaum. The value for a(4) was given by George Olshevsky in 2006.
Deza and Shtogrin (2000) agree that the value of a(3) is 28, although the authors do not provide a proof. - Felix Fröhlich, Nov 29 2014
From Felix Fröhlich, Feb 03 2019: (Start)
The 11 convex uniform tilings are all illustrated in Kepler, 1619. For an argument that exactly 11 such tilings exist, see Grünbaum, Shephard, 1977.
In dimension 2, the definition of "uniform polytope" usually seems to be equivalent to the regular polygons in order to exclude polygons that alternate two different edge-lengths. Applying this principle retroactively to dimension 1 (as done, as I assume, by Coxeter, see Coxeter, 1973, p. 129) yields a(1) = 1. (End)

References

  • H. S. M. Coxeter, Regular Polytopes, Third Edition, Dover Publications, 1973, ISBN 9780486614809.
  • B. Grünbaum, Uniform tilings of 3-space, Geombinatorics, Vol. 4, No. 2 (1994), 49-56.
  • N. W. Johnson, Uniform Polytopes, [To appear, cf. Weiss, Stehle, 2017].

Crossrefs

Cf. A068599.
List of coordination sequences for the 11 uniform 2D tilings: A008458(the planar net 3.3.3.3.3.3), A008486 (6^3), A008574 (4.4.4.4 and 3.4.6.4), A008576 (4.8.8), A008579 (3.6.3.6), A008706(3.3.3.4.4), A072154 (4.6.12), A219529 (3.3.4.3.4), A250120(3.3.3.3.6), A250122 (3.12.12).
List of coordination sequences for the 28 uniform 3D tilings: cab: A299266, A299267; crs: A299268, A299269; fcu: A005901, A005902; fee: A299259, A299265; flu-e: A299272, A299273; fst: A299258, A299264; hal: A299274, A299275; hcp: A007899, A007202; hex: A005897, A005898; kag: A299256, A299262; lta: A008137, A299276; pcu: A005899, A001845; pcu-i: A299277, A299278; reo: A299279, A299280; reo-e: A299281, A299282; rho: A008137, A299276; sod: A005893, A005894; sve: A299255, A299261; svh: A299283, A299284; svj: A299254, A299260; svk: A010001, A063489; tca: A299285, A299286; tcd: A299287, A299288; tfs: A005899, A001845; tsi: A299289, A299290; ttw: A299257, A299263; ubt: A299291, A299292; bnn: A007899, A007202. See the Proserpio link in A299266 for overview.

Extensions

Edited by N. J. A. Sloane, Feb 15 2018
Edited by Felix Fröhlich, Feb 03-10 2019

A250121 Crystal ball sequence for planar net 3.3.3.3.6.

Original entry on oeis.org

1, 6, 15, 30, 49, 73, 102, 135, 174, 217, 265, 318, 375, 438, 505, 577, 654, 735, 822, 913, 1009, 1110, 1215, 1326, 1441, 1561, 1686, 1815, 1950, 2089, 2233, 2382, 2535, 2694, 2857, 3025, 3198, 3375, 3558, 3745, 3937, 4134
Offset: 0

Views

Author

Bradley Klee and N. J. A. Sloane, Nov 23 2014

Keywords

Comments

The g.f. was proven; cf. the comment in A250120. - Georg Fischer, Jul 19 2020

Crossrefs

Partial sums of A250120.

Programs

  • Mathematica
    CoefficientList[Series[(x^2+x+1)*(x^4+3*x^3+3*x+1)/((x^4+x^3+x^2+x+1)*(1-x)^3),{x,0,41}],x] (* Georg Fischer, Jul 19 2020 *)
    LinearRecurrence[{2,-1,0,0,1,-2,1},{1,6,15,30,49,73,102},50] (* Harvey P. Dale, Apr 30 2022 *)

Formula

G.f.: (x^2+x+1)*(x^4+3*x^3+3*x+1)/((x^4+x^3+x^2+x+1)*(1-x)^3).

A310387 Coordination sequence Gal.6.588.6 where Gal.u.t.v denotes the coordination sequence for a vertex of type v in tiling number t in the Galebach list of u-uniform tilings.

Original entry on oeis.org

1, 4, 10, 14, 18, 26, 30, 34, 38, 42, 54, 50, 58, 62, 74, 70, 78, 78, 98, 86, 98, 98, 118, 106, 118, 114, 142, 122, 138, 134, 162, 142, 158, 150, 186, 158, 178, 170, 206, 178, 198, 186, 230, 194, 218, 206, 250, 214, 238, 222
Offset: 0

Views

Author

Brian Galebach and N. J. A. Sloane, Jun 18 2018

Keywords

Comments

Note that there may be other vertices in the Galebach list of u-uniform tilings with u <= 6 that have this same coordination sequence. See the Galebach link for the complete list of A-numbers for all these tilings.

A311019 Coordination sequence Gal.6.492.2 where Gal.u.t.v denotes the coordination sequence for a vertex of type v in tiling number t in the Galebach list of u-uniform tilings.

Original entry on oeis.org

1, 4, 8, 11, 12, 16, 24, 29, 34, 30, 32, 43, 50, 52, 58, 53, 56, 58, 70, 81, 82, 78, 76, 83, 96, 96, 104, 105, 98, 108, 114, 123, 132, 118, 122, 131, 138, 150, 150, 147, 148, 142, 162, 171, 176, 176, 164, 173, 184, 184
Offset: 0

Views

Author

Brian Galebach and N. J. A. Sloane, Jun 18 2018

Keywords

Comments

Note that there may be other vertices in the Galebach list of u-uniform tilings with u <= 6 that have this same coordination sequence. See the Galebach link for the complete list of A-numbers for all these tilings.

A315211 Coordination sequence Gal.3.20.3 where Gal.u.t.v denotes the coordination sequence for a vertex of type v in tiling number t in the Galebach list of u-uniform tilings.

Original entry on oeis.org

1, 6, 10, 14, 20, 26, 30, 34, 40, 46, 50, 54, 60, 66, 70, 74, 80, 86, 90, 94, 100, 106, 110, 114, 120, 126, 130, 134, 140, 146, 150, 154, 160, 166, 170, 174, 180, 186, 190, 194, 200, 206, 210, 214, 220, 226, 230, 234, 240, 246
Offset: 0

Views

Author

Brian Galebach and N. J. A. Sloane, Jun 18 2018

Keywords

Comments

Note that there may be other vertices in the Galebach list of u-uniform tilings with u <= 6 that have this same coordination sequence. See the Galebach link for the complete list of A-numbers for all these tilings.
Previous Showing 61-70 of 6133 results. Next