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

1,2

Comments

This sequence has similarities with A236266.

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

Example

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

Prog

(C#) See Links section.

Crossrefs

See A333835 and A333866 for a similar sequences.

Cf. A174344, A236266, A274923.

Sequence in context: A333835 A178683 A111191 * A115891 A359230 A293035

Adjacent sequences: A333822 A333823 A333824 * A333826 A333827 A333828

Keyword

nonn

Author

Rémy Sigrist, Apr 07 2020

Status

approved