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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A346785 Denominators of minimal squared radii of circular disks covering a record number of lattice points of the hexagonal lattice, when the centers of the circles are chosen to maximize the number of covered lattice points.

Original entry on oeis.org

1, 4, 3, 4, 1, 4, 25, 4, 3, 4, 48, 25, 1, 27, 4, 64, 289, 27, 3, 1, 121, 16, 1, 4, 2187, 48, 3, 841, 27, 289, 4, 64, 1, 25, 64, 121, 4, 1
Offset: 1

Views

Author

Hugo Pfoertner, Aug 08 2021

Keywords

Examples

			0, 1/4, 1/3, 3/4, 1, 7/4, 49/25, 9/4, 7/3, 13/4, 169/48, 91/25, 4, 133/27, 21/4, 361/64, 1729/289, 169/27, 19/3, 7, 961/121, 133/16, 9, ...

Crossrefs

Corresponding numerators are A346784.
Cf. A125852, A346126.

A224876 On an hexagonal lattice, repeatedly: mark the current point and then move forward to the nearest unmarked point and then rotate 120 degrees clockwise. a(n) gives the number of steps between the n-th and (n+1)-th marks.

Original entry on oeis.org

1, 1, 2, 1, 2, 1, 3, 1, 3, 1, 4, 1, 4, 1, 5, 1, 5, 1, 6, 1, 3, 1, 3, 4, 3, 4, 3, 5, 1, 3, 1, 6, 3, 6, 3, 7, 1, 6, 1, 8, 1, 6, 1, 7, 3, 8, 3, 8, 1, 8, 1, 9, 1, 9, 1, 10, 1, 2, 1, 3, 10, 3, 10, 3, 1, 2, 1, 12, 1, 3, 1, 5, 1, 2, 1, 12, 1, 3, 1, 5, 9, 4, 11, 1, 2, 1
Offset: 1

Views

Author

Paul Tek, Jul 23 2013

Keywords

Comments

Apparently, every lattice point will be marked.

Examples

			This diagram depicts the first 9 marks:
  \ / \ / \ /
--4---5---.--
  / \ / \ / \
-7---1---2---8-
  \ / \ / \ / \
--6---3---9--
  / \ / \ / \
a(1) = number of steps between 1st and 2nd marks = 1;
a(2) = number of steps between 2nd and 3rd marks = 1;
a(3) = number of steps between 3rd and 4th marks = 2;
a(4) = number of steps between 4th and 5th marks = 1;
a(5) = number of steps between 5th and 6th marks = 2;
a(6) = number of steps between 6th and 7th marks = 1;
a(7) = number of steps between 7th and 8th marks = 3;
a(8) = number of steps between 8th and 9th marks = 1.

Links

Crossrefs

Cf. A001334, A125852.

Programs

  • Perl
    See Links section.
Previous Showing 11-12 of 12 results.

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