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 1-8 of 8 results.

A360352 Number of regions among all distinct circles that can be constructed from an n X n square grid of points when each pair of points is connected by a circle and the points lie at the ends of a diameter of the circle.

Original entry on oeis.org

12, 168, 1536, 8904, 36880, 123468, 358036, 912776, 2105976
Offset: 2

Views

Author

Scott R. Shannon, Feb 04 2023

Keywords

Comments

A circle is constructed for every pair of points on the n X n grid, the points lying at the ends of a diameter of the circle. The number of distinct circles constructed from the n X n grid is A360350(n).

Crossrefs

Cf. A360351 (vertices), A360353 (edges), A360354 (k-gons), A360350 (distinct circles), A359933.

Formula

a(n) = A360353(n) - A360351(n) + 1 by Euler's formula.

A360354 Irregular table read by rows: T(n,k) is the number of k-gons, k>=2, among all distinct circles that can be constructed from an n x n square grid of points when each pair of points is connected by a circle and the points lie at the ends of a diameter of the circle.

Original entry on oeis.org

8, 4, 40, 108, 20, 92, 904, 456, 76, 0, 8, 200, 4540, 3400, 652, 100, 4, 8, 404, 17244, 15324, 3148, 628, 116, 16, 528, 54252, 54476, 11672, 2152, 332, 44, 12, 972, 151992, 158468, 37244, 7940, 1120, 224, 48, 12, 16, 1404, 379488, 404148, 103436, 20216, 3316, 600, 132, 20, 16
Offset: 2

Views

Author

Scott R. Shannon, Feb 04 2023

Keywords

Comments

A circle is constructed for every pair of points on the n X n grid, the points lying at the ends of a diameter of the circle.
The number of distinct circles constructed from the n x n grid is A360350(n).
See A360351 and A360352 for images of the circles.

Examples

			The table begins:
8, 4;
40, 108, 20;
92, 904, 456, 76, 0, 8;
200, 4540, 3400, 652, 100, 4, 8;
404, 17244, 15324, 3148, 628, 116, 16;
528, 54252, 54476, 11672, 2152, 332, 44, 12;
972, 151992, 158468, 37244, 7940, 1120, 224, 48, 12, 16;
1404, 379488, 404148, 103436, 20216, 3316, 600, 132, 20, 16;
1896, 868460, 923656, 252096, 49848, 7916, 1744, 276, 84;
.
.
		

Crossrefs

Cf. A360351 (vertices), A360352 (regions), A360353 (edges), A360354 (k-gons), A360350 (distinct circles), A359935.

Formula

Sum of row n = A360352(n).

A360350 Number of distinct circles that can be constructed from an n X n square grid of points when each pair of points is connected by a circle and the points lie at the ends of a diameter of the circle.

Original entry on oeis.org

5, 26, 79, 185, 366, 653, 1077, 1678, 2494, 3571, 4959, 6718, 8889, 11541, 14740, 18553, 23027, 28278, 34351, 41352, 49356, 58454, 68732, 80330, 93304, 107757, 123815, 141605, 161211, 182795, 206393, 232190, 260331, 290907, 324090, 360080, 398856, 440655, 485655
Offset: 2

Views

Author

Scott R. Shannon, Feb 03 2023

Keywords

Comments

A circle is constructed for every pair of points on the n X n grid, the points lying at the ends of a diameter of the circle.
No formula for a(n) is known.
See A360351 and A360352 for images of the resulting vertices and regions.

Crossrefs

Cf. A360351 (vertices), A360352 (regions), A360353 (edges), A360354 (k-gons), A359931.

Programs

  • PARI
    a(n) = { my (p = vector(n^2, k, (k-1)%n + ((k-1)\n)*I)); #setbinop((i,j)->[i+j, norm(i-j)], p)-n^2; } \\ Rémy Sigrist, Sep 24 2023

Extensions

More terms from Rémy Sigrist, Sep 24 2023

A360353 Number of edges among all distinct circles that can be constructed from an n X n square grid of points when each pair of points is connected by a circle and the points lie at the ends of a diameter of the circle.

Original entry on oeis.org

16, 244, 2580, 15788, 67144, 227888, 668008, 1712960, 3968028
Offset: 2

Views

Author

Scott R. Shannon, Feb 04 2023

Keywords

Comments

A circle is constructed for every pair of points on the n X n grid, the points lying at the ends of a diameter of the circle. The number of distinct circles constructed from the n X n grid is A360350(n).
See A360351 and A360352 for images of the circles.

Crossrefs

Cf. A360351 (vertices), A360352 (regions), A360354 (k-gons), A360350 (distinct circles), A359934.

Formula

a(n) = A360351(n) + A360352(n) - 1 by Euler's formula.

A372614 Number of vertices among all distinct circles that can be constructed from the 3 vertices and the equally spaced 3*n points placed on the sides of an equilateral triangle, using only a compass.

Original entry on oeis.org

6, 87, 481, 1992, 6969, 15409, 35202, 58422, 107677, 159138, 268572, 350860, 557049
Offset: 0

Views

Author

Scott R. Shannon, May 07 2024

Keywords

Comments

A circle is constructed for every pair of the 3 + 3*n points, the first point defines the circle's center while the second the radius distance.

Crossrefs

Cf. A372615 (regions), A372616 (edges), A372617 (k-gons), A372682 (number of circles), A372731, A371373, A354605, A360351.

Formula

a(n) = A372616(n) - A372615(n) + 1 by Euler's formula.

A372731 Number of vertices among all distinct circles that can be constructed from the 3 vertices and the equally spaced 3*n points placed on the sides of an equilateral triangle when every pair of the 3 + 3*n points are connected by a circle and where the points lie at the ends of the circle's diameter.

Original entry on oeis.org

6, 51, 301, 1272, 3285, 8401, 16050, 30036, 49801, 80916, 120447, 180307, 249108, 350145, 465898, 618213
Offset: 0

Views

Author

Scott R. Shannon, May 12 2024

Keywords

Comments

A circle is constructed for every pair of the 3 + 3*n points, the two points lying at the ends of a diameter of the circle.

Crossrefs

Cf. A372732 (regions), A372733 (edges), A372734 (k-gons), A372735 (number of circles), A372614, A371373, A354605, A360351.

Formula

a(n) = A372733(n) - A372732(n) + 1 by Euler's formula.

A372977 Number of vertices among all distinct circles that can be constructed from the 4 vertices and the equally spaced 4*n points placed on the sides of a square, using only a compass.

Original entry on oeis.org

40, 553, 4204, 14505, 39004, 94365, 197464, 320925, 569600
Offset: 0

Views

Author

Scott R. Shannon, May 19 2024

Keywords

Comments

A circle is constructed for every pair of the 4 + 4*n points, the first point defines the circle's center while the second the radius distance.

Crossrefs

Cf. A372978 (regions), A372979 (edges), A372980 (k-gons), A372981 (circles), A372614, A372731, A371373, A354605, A360351.

Formula

a(n) = A372979(n) - A372978(n) + 1 by Euler's formula.

A373106 Number of vertices among all distinct circles that can be constructed from the 4 vertices and the equally spaced 4*n points placed on the sides of a square when every pair of the 4 + 4*n points are connected by a circle and where the points lie at the ends of the circle's diameter.

Original entry on oeis.org

5, 61, 677, 2533, 7705, 17269, 37161, 65089, 111877, 174545, 274213
Offset: 0

Views

Author

Scott R. Shannon, May 25 2024

Keywords

Comments

A circle is constructed for every pair of the 4 + 4*n points, the two points lying at the ends of a diameter of the circle.

Crossrefs

Cf. A373107 (regions), A373108 (edges), A373109 (k-gons), A373110 (circles), A372977, A372731, A358746, A362233, A360351.

Formula

a(n) = A373108(n) - A373107(n) + 1 by Euler's formula.
Showing 1-8 of 8 results.