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.

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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

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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

A298562 Quantitative (polygonal) Helly numbers for the integer lattice Z^2.

Original entry on oeis.org

4, 6, 6, 6, 8, 7, 8, 9, 8, 8, 10, 9, 9, 10, 10, 10, 10, 11, 11, 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, 17, 17, 17
Offset: 0

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Author

Keywords

Comments

a(n) = g(Z^2,n) is the maximum integer k > 0 such that there exists a lattice polygon with k vertices containing exactly n+k lattice points (in its interior or on the boundary). [edited by Günter Rote, Oct 01 2023]

Examples

			a(18) = 11 (so this sequence differs from A322345), attained only by the following polygon (No. 3736 in the corresponding list in Castryck's file) with 11 vertices, 1 non-vertex boundary lattice point, and genus (number of internal lattice points) 17: [(-2, -1), (-1, -2), (1, -2), (3, -1), (4, 0), (4, 1), (3, 2), (1, 3), (0, 3), (-1, 2), (-2, 0)].
		

Crossrefs

Programs

  • Python
    # See the Python program for A322345.

Extensions

a(31) onwards from Günter Rote, Oct 01 2023
Showing 1-2 of 2 results.