A361299 Counterclockwise spiral constructed of distinct terms such that any two terms a knight's move apart are coprime; always choose the smallest possible positive term.

1, 2, 3, 4, 5, 7, 9, 8, 11, 10, 13, 6, 15, 12, 17, 14, 19, 16, 23, 18, 25, 20, 29, 22, 21, 24, 31, 26, 37, 28, 35, 32, 41, 34, 43, 27, 33, 36, 47, 44, 39, 38, 49, 40, 53, 46, 59, 30, 51, 50, 61, 55, 67, 58, 71, 52, 45, 56, 73, 62, 65, 64, 79, 42, 77, 48, 83

Offset: 1

Author

Jodi Spitz, Mar 08 2023

Keywords

• nonn

Examples

			The spiral begins:
  33--27--43--34--41--32--35
   |                       |
  36  19--14--17--12--15  28
   |   |               |   |
  47  16   5---4---3   6  37
   |   |   |       |   |   |
  44  23   7   1---2  13  26
   |   |   |           |   |
  39  18   9---8--11--10  31
   |   |                   |
  38  25--20--29--22--21--24
   |
  49--40--53--46---.---.---.
		

Links

• Jodi Spitz, Table of n, a(n) for n = 1..4002
• Rémy Sigrist, PARI program

Crossrefs

Cf. A308884.

Programs

PARI

See Links section.

Extensions

More terms from Rémy Sigrist, Mar 09 2023