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

Author

Rémy Sigrist, Apr 07 2020

Keywords

• nonn

Comments

This sequence has similarities with A005836 and A229037.

Examples

			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
		

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

Crossrefs

See A333825 for a similar sequences.

Cf. A005836, A174344, A229037, A274923.