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

1,2

Links

Jodi Spitz, Table of n, a(n) for n = 1..4002

Rémy Sigrist, PARI program

Example

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---.---.---.

Prog

(PARI) See Links section.

Crossrefs

Cf. A308884.

Sequence in context: A354126 A245820 A105362 * A115928 A247665 A117331

Adjacent sequences: A361296 A361297 A361298 * A361300 A361301 A361302

Keyword

nonn

Author

Jodi Spitz, Mar 08 2023

Extensions

More terms from Rémy Sigrist, Mar 09 2023

Status

approved