A333825 - OEIS

%I #15 Apr 12 2020 13:57:57

%S 1,2,3,4,17,20,22,27,45,48,67,79,80,131,135,174,180,194,201,209,236,

%T 254,312,319,394,523,644,656,706,711,733,765,766,845,848,921,922,935,

%U 1034,1051,1219,1292,1310,1330,1399,1410,1546,1589,1674,1792,1816,1863

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

%C This sequence has similarities with A236266.

%H Rémy Sigrist, <a href="/A333825/b333825.txt">Table of n, a(n) for n = 1..10000</a>

%H Rémy Sigrist, <a href="/A333825/a333825.png">Scatterplot of (A174344(a(n)), A274923(a(n))) in the region -20000 <= x, y <= 20000</a>

%H Rémy Sigrist, <a href="/A333825/a333825.txt">C# program for A333825</a>

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

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

%e          |                               |

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

%e          |   |                       |   |

%e         67   *  17---*---*---*---*   *   *

%e          |   |   |               |   |   |

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

%e          |   |   |   |       |   |   |   |

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

%e          |   |   |   |           |   |   |

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

%e          |   |   |                   |   |

%e          *   *   *--22---*---*---*---*   *

%e          |   |                           |

%e          *   *---*--45---*---*--48---*---*

%e          |

%e          *---*---*---*---*---*--79--80---*

%o (C#) See Links section.

%Y See A333835 and A333866 for a similar sequences.

%Y Cf. A174344, A236266, A274923.

%K nonn

%O 1,2

%A _Rémy Sigrist_, Apr 07 2020