A333825 Lexicographically earliest sequence of distinct positive integers, which when mapped onto a square spiral, gives a set without three distinct aligned points.

1, 2, 3, 4, 17, 20, 22, 27, 45, 48, 67, 79, 80, 131, 135, 174, 180, 194, 201, 209, 236, 254, 312, 319, 394, 523, 644, 656, 706, 711, 733, 765, 766, 845, 848, 921, 922, 935, 1034, 1051, 1219, 1292, 1310, 1330, 1399, 1410, 1546, 1589, 1674, 1792, 1816, 1863

Offset: 1

Author

Rémy Sigrist, Apr 07 2020

Keywords

• nonn

Comments

This sequence has similarities with A236266.

Examples

			The first terms, mapped onto a square spiral, are:
         *---*---*---*---*---*---*---*---*
         |                               |
         *   *---*---*---*---*---*---*   *
         |   |                       |   |
        67   *  17---*---*---*---*   *   *
         |   |   |               |   |   |
         *   *   *   *---4---3   *   *   *
         |   |   |   |       |   |   |   |
         *   *   *   *   1---2   *   *   *
         |   |   |   |           |   |   |
         *   *  20   *---*---*---*  27   *
         |   |   |                   |   |
         *   *   *--22---*---*---*---*   *
         |   |                           |
         *   *---*--45---*---*--48---*---*
         |
         *---*---*---*---*---*--79--80---*
		

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 -20000 <= x, y <= 20000
• Rémy Sigrist, C# program for A333825

Crossrefs

See A333835 and A333866 for a similar sequences.

Cf. A174344, A236266, A274923.