A333835 Lexicographically earliest sequence of distinct positive integers, which when mapped onto a square spiral, gives a set without three distinct evenly spaced aligned points.

1, 2, 3, 4, 17, 18, 20, 21, 22, 24, 27, 28, 31, 33, 34, 61, 80, 81, 87, 90, 93, 100, 131, 135, 145, 146, 148, 152, 154, 157, 158, 160, 166, 171, 172, 174, 189, 194, 225, 253, 268, 270, 271, 276, 281, 282, 291, 294, 295, 298, 316, 335, 338, 368, 383, 397, 405

Offset

1,2

Comments

This sequence has similarities with A005836 and A229037.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, Scatterplot of (A174344(a(n)), A274923(a(n))) in the region -10000 <= x, y <= 10000

Rémy Sigrist, C# program for A333835

Example

The first terms, mapped onto a square spiral, are:
         *---*---*---*--61---*---*---*---*
         |                               |
         *   *---*---*--34--33---*--31   *
         |   |                       |   |
         *   *  17---*---*---*---*   *   *
         |   |   |               |   |   |
         *   *  18   *---4---3   *   *   *
         |   |   |   |       |   |   |   |
         *   *   *   *   1---2   *  28   *
         |   |   |   |           |   |   |
         *   *  20   *---*---*---*  27   *
         |   |   |                   |   |
         *   *  21--22---*--24---*---*   *
         |   |                           |
         *   *---*---*---*---*---*---*---*
         |
         *---*---*---*---*---*---*--80--81

Prog

(C#) See Links section.

Crossrefs

See A333825 for a similar sequences.

Cf. A005836, A174344, A229037, A274923.

Sequence in context: A343494 A300855 A353164 * A178683 A111191 A333825

Adjacent sequences: A333832 A333833 A333834 * A333836 A333837 A333838

Keyword

nonn

Author

Rémy Sigrist, Apr 07 2020

Status

approved