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 1-3 of 3 results.

A343385 The ordered square spiral numbers visited by the knight in A343356.

Original entry on oeis.org

1, 10, 29, 2, 5, 40, 7, 4, 11, 26, 83, 174, 123, 84, 27, 12, 15, 18, 35, 64, 97, 36, 65, 142, 63, 66, 149, 102, 143, 146, 103, 100, 141, 62, 33, 58, 55, 28, 87, 178, 131, 92, 31, 54, 13, 60, 139, 248, 191, 316, 247, 136, 91, 182, 185, 132, 237, 300, 371, 450, 295, 228, 173, 82, 49, 78, 45, 74
Offset: 1

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Author

Scott R. Shannon, Apr 13 2021

Keywords

Comments

This is the ordered square-spiral numbers visited by a knight on a square spiral as numbered in A343356. See that sequence for further details.

Crossrefs

A343388 Squares visited by a knight moving on a square-spiral with numbers equal to the ordered divisors of the positive integers and where the knight moves to the smallest numbered unvisited square; the minimum distance from the origin is used if the square numbers are equal; the smallest ordered spiral number is used if the distances are equal.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 4, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 2, 2, 1, 1, 1, 2, 1, 5, 1, 1, 3, 1, 4, 1, 1, 8, 1, 3, 2, 2, 3, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Scott R. Shannon, Apr 13 2021

Keywords

Comments

Many of the visited squares are numbered 1 due to the large number of such terms on the board and the knight's preference for the lowest available numbered square.
The sequence is finite. After 358 steps the square with spiral number 13, with ordered spiral number 37, is reached after which all eight adjacent squares have been visited. The visited square with the largest spiral number is 28.
See A343389 for the visited squares given as the ordered spiral numbers.

Examples

			The square-spiral is numbered with the ordered divisors of the positive integers as follows:
.
   1---7---1---6---3   .
   |               |   .
   2   3---1---2   2   11
   |   |       |   |   |
   4   1   1---1   1   1
   |   |           |   |
   8   2---4---1---5   10
   |                   |
   1---3---9---1---2---5
.
a(1) = 1, the starting square of the knight.
a(2) = 1. One square numbered 1 can be stepped to from the starting square, the square with coordinates (1,-2) relative to that square.
a(9) = 2. This is the first time a square greater than 1 is stepped to. The available squares after 7 steps are 3, 11, 10, 2, 9, 2, and 3. The 2 at coordinates (-1,-1) relative to the starting square is because it is the closest number to that square.
a(146) = 28. This is the largest numbered square that is stepped to. The available squares after the 144th step are 117, 213, 47, 70, 61, and 28, and 28 is the smallest of these.
a(359) = 13. This is the final square stepped to as no further unvisited square is available.
		

Crossrefs

A343389 The ordered square-spiral numbers visited by the knight in A343388.

Original entry on oeis.org

1, 24, 11, 4, 9, 6, 15, 2, 7, 46, 21, 72, 75, 42, 19, 38, 105, 202, 151, 104, 147, 262, 199, 102, 67, 36, 61, 32, 3, 28, 51, 124, 85, 128, 53, 30, 59, 96, 141, 250, 189, 316, 251, 392, 315, 474, 563, 660, 769, 1006, 767, 658, 879, 762, 555, 462, 553, 756, 873, 998, 761, 556, 381, 460, 305
Offset: 1

Views

Author

Scott R. Shannon, Apr 13 2021

Keywords

Comments

This is the ordered square-spiral numbers visited by a knight on a square spiral as numbered in A343388. See that sequence for further details.

Crossrefs

Showing 1-3 of 3 results.