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 13 results. Next

A187015 The number of different classes of 2-dimensional convex lattice polytopes having volume n/2 up to unimodular equivalence.

Original entry on oeis.org

1, 2, 3, 7, 6, 13, 13, 27, 26, 44, 43, 83, 81, 122, 136, 208, 215, 317, 341, 490, 542, 710, 778, 1073, 1186, 1519, 1708, 2178, 2405, 3042, 3408, 4247, 4785, 5782, 6438, 7870, 8833, 10560, 11857, 14131, 15733, 18636, 20773, 24381, 27353, 31764, 35284, 41081, 45791, 52762
Offset: 1

Views

Author

Jonathan Vos Post, Mar 01 2011

Keywords

Comments

Lattice polytopes up to the equivalence relation used here are also called toric diagrams, see references below. - Andrey Zabolotskiy, May 10 2019
Liu & Zong give a(7) = 11, and others use their list, but their list lacks polygons No. 3 and 4 from Balletti's file 2-polytopes/v7.txt. - Andrey Zabolotskiy, Dec 28 2021

Crossrefs

Cf. A126587, A003051 (triangles only), A322343, A366409.

Programs

  • Python
    # See the Python program for A366409.

Extensions

a(8) from Yan Xiao added by Andrey Zabolotskiy, May 10 2019
Name edited, a(7) corrected, a(9)-a(50) added using Balletti's data by Andrey Zabolotskiy, Dec 28 2021

A322345 Maximal number of vertices of a convex lattice polygon containing n lattice points in its interior.

Original entry on oeis.org

4, 6, 6, 6, 8, 7, 8, 9, 8, 8, 10, 9, 9, 10, 10, 10, 10, 11, 10, 12, 12, 12, 11, 11, 12, 12, 12, 13, 12, 12, 13, 13, 13, 13, 14, 14, 13, 13, 14, 14, 14, 14, 14, 14, 14, 15, 14, 15, 15, 15, 15, 15, 16, 15, 16, 15, 16, 16, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 16, 17, 17, 16, 17, 17
Offset: 0

Views

Author

Hugo Pfoertner, Dec 04 2018

Keywords

Comments

This is an inverse of A063984 in the following sense: A063984(k) = min {n : a(n)>=k}. Thus a(n) grows roughly like const*n^(1/3). - Günter Rote, Sep 19 2023

Crossrefs

Programs

  • Python
    # See the Python program in the links section.

Extensions

a(0) added by Andrey Zabolotskiy, Dec 29 2021
Name clarified by Günter Rote, Sep 18 2023
a(31) onwards from Günter Rote, Oct 01 2023

A371917 Number of inequivalent convex lattice polygons containing n lattice points (including points on the boundary).

Original entry on oeis.org

1, 3, 6, 13, 21, 41, 67, 111, 175, 286, 419, 643, 938, 1370, 1939, 2779, 3819, 5293, 7191, 9752, 12991, 17321, 22641, 29687, 38533, 49796, 63621, 81300, 102807, 129787, 162833, 203642, 252898, 313666, 386601, 475540, 582216, 710688, 863552, 1048176
Offset: 3

Views

Author

Justus Springer, Apr 12 2024

Keywords

Comments

A322343 counts the polygons by their number of interior lattice points, excluding points on the boundary.

Examples

			For n = 3, the only polygon is the standard triangle with vertices (0,0), (1,0) and (0,1).
For n = 4, a(4) = 3 and the three polygons have vertex sets {(1,0),(0,1),(-1,-1)}, {(0,0),(2,0),(0,1)} and {(0,0),(1,0),(0,1),(1,1)}.
		

Crossrefs

A322344 Number of equivalence classes of convex lattice polygons of genus n, restricting the count to those polygons that are interior to another polygon.

Original entry on oeis.org

16, 22, 63, 78, 122, 192, 239, 316, 508, 509, 700, 1044, 1113, 1429, 2052, 1962, 2651, 3543, 3638, 4594, 5996, 6364, 7922, 9692, 10208, 12727, 15431, 15918, 20354, 23873, 24677, 31593, 36529, 37302, 46034, 54454, 56278, 67020, 79606, 82549, 98188, 113752
Offset: 1

Views

Author

Hugo Pfoertner, Dec 04 2018

Keywords

Comments

See Castryck article for an explanation how to check if a polygon is interior to another polygon by application of theorem 5 (Koelman 1991).

References

Crossrefs

Cf. A322343.

Extensions

a(24) and a(30) corrected, a(31) onwards added by Justus Springer, Oct 26 2024

A322348 Maximal lattice width of a convex lattice polygon containing n lattice points in its interior ("of genus n").

Original entry on oeis.org

2, 3, 2, 4, 4, 4, 5, 4, 4, 5, 6, 5, 6, 6, 6, 7, 6, 6, 7, 8, 7, 8, 8, 8, 8, 8, 8, 8, 9, 8, 9
Offset: 0

Views

Author

Hugo Pfoertner, Dec 04 2018

Keywords

Crossrefs

Extensions

a(0) added and name clarified by Andrey Zabolotskiy, Sep 21 2023

A322346 Maximal number of vertices of a convex lattice polygon of genus n, restricted to those polygons that are interior to another polygon.

Original entry on oeis.org

6, 6, 6, 8, 7, 8, 9, 8, 8, 10, 9, 9, 10, 10, 10, 10, 11, 10, 12, 11, 12, 11, 11, 12, 12, 12, 12, 12, 12, 12
Offset: 1

Views

Author

Hugo Pfoertner, Dec 04 2018

Keywords

References

Crossrefs

A322349 Maximal lattice width of a convex lattice polygon of genus n, restricted to those polygons that are interior to another polygon.

Original entry on oeis.org

3, 2, 4, 4, 4, 5, 4, 4, 5, 6, 5, 6, 6, 6, 7, 6, 6, 7, 8, 7, 8, 8, 7, 8, 8, 8, 8, 9, 8, 9
Offset: 1

Views

Author

Hugo Pfoertner, Dec 04 2018

Keywords

Comments

Sequence first differs from A322348 at n = 23.

References

Crossrefs

A322347 Minimal number of vertices of a convex lattice polygon of genus n, restricted to those polygons that are interior to another polygon.

Original entry on oeis.org

3, 4, 3, 3, 3, 3, 3, 4, 3, 3, 4, 4, 3, 4, 3, 3, 4, 4, 3, 4, 3, 4, 4, 4, 3, 4, 4, 3, 4, 4
Offset: 1

Views

Author

Hugo Pfoertner, Dec 04 2018

Keywords

Comments

Without the restriction to polygons that are interior to another polygon, the minimal number of vertices is always 3.

References

Crossrefs

Cf. A322343.

A322350 Minimal number of points on the boundary of a convex lattice polygon of genus n, restricted to those polygons that are interior to another polygon.

Original entry on oeis.org

3, 5, 5, 6, 7, 6, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 10, 9, 9, 10, 10, 10, 10, 10, 11, 9, 10, 11, 11
Offset: 1

Views

Author

Hugo Pfoertner, Dec 04 2018

Keywords

Comments

Without the restriction to polygons that are interior to another polygon, the minimal number of points on the boundary is always 3.

References

Crossrefs

Cf. A322343.

A374975 Number of equivalence classes of lattice polygons contained in a square of side length n but not in a square of side length n-1.

Original entry on oeis.org

2, 15, 131, 1369, 13842, 129185, 1104895, 8750964, 64714465, 450686225, 2976189422
Offset: 1

Views

Author

Justus Springer, Jul 26 2024

Keywords

Examples

			For n = 1, only the square itself and the standard triangle are contained in the square, so a(1) = 2.
		

Crossrefs

Showing 1-10 of 13 results. Next