A333835 - OEIS

%I #15 Apr 12 2020 13:58:09

%S 1,2,3,4,17,18,20,21,22,24,27,28,31,33,34,61,80,81,87,90,93,100,131,

%T 135,145,146,148,152,154,157,158,160,166,171,172,174,189,194,225,253,

%U 268,270,271,276,281,282,291,294,295,298,316,335,338,368,383,397,405

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

%C This sequence has similarities with A005836 and A229037.

%H Rémy Sigrist, <a href="/A333835/b333835.txt">Table of n, a(n) for n = 1..10000</a>

%H Rémy Sigrist, <a href="/A333835/a333835.png">Scatterplot of (A174344(a(n)), A274923(a(n))) in the region -10000 <= x, y <= 10000</a>

%H Rémy Sigrist, <a href="/A333835/a333835.txt">C# program for A333835</a>

%e The first terms, mapped onto a square spiral, are:

%e          *---*---*---*--61---*---*---*---*

%e          |                               |

%e          *   *---*---*--34--33---*--31   *

%e          |   |                       |   |

%e          *   *  17---*---*---*---*   *   *

%e          |   |   |               |   |   |

%e          *   *  18   *---4---3   *   *   *

%e          |   |   |   |       |   |   |   |

%e          *   *   *   *   1---2   *  28   *

%e          |   |   |   |           |   |   |

%e          *   *  20   *---*---*---*  27   *

%e          |   |   |                   |   |

%e          *   *  21--22---*--24---*---*   *

%e          |   |                           |

%e          *   *---*---*---*---*---*---*---*

%e          |

%e          *---*---*---*---*---*---*--80--81

%o (C#) See Links section.

%Y See A333825 for a similar sequences.

%Y Cf. A005836, A174344, A229037, A274923.

%K nonn

%O 1,2

%A _Rémy Sigrist_, Apr 07 2020