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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
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
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
KEYWORD
nonn
AUTHOR
Jodi Spitz, Mar 08 2023
EXTENSIONS
More terms from Rémy Sigrist, Mar 09 2023
STATUS
approved