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A338288 Squares visited by the white knight when a white knight and a black knight are moving on a spirally numbered board, always to the lowest available unvisited square; white moves first. 5
1, 10, 3, 6, 15, 2, 5, 8, 11, 24, 27, 48, 23, 20, 39, 16, 19, 22, 41, 44, 71, 74, 45, 42, 69, 38, 6, 66, 99, 36, 61, 94, 31, 54, 85, 124, 51, 80, 83, 120, 123, 168, 81, 118, 77, 114, 73, 108, 151, 68, 103, 64, 67, 102, 143, 146, 195, 100, 141, 96, 137, 60, 93, 90, 129, 86, 125, 172, 121, 166, 117, 162, 113, 110, 153 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Board is numbered with the square spiral:
17--16--15--14--13 .
| | .
18 5---4---3 12 .
| | | | .
19 6 1---2 11 .
| | | .
20 7---8---9--10 .
| .
21--22--23--24--25--26
Both knights start on square 1, white moves to the lowest unvisited square (10), black then moves to the lowest unvisited square (12) and so on...
This sequence is finite, on the white knight's 3999th step, square 3606 is visited, after which there are no unvisited squares within one knight move.
The sequences generated by 4 knights and 8 knights also produce new sequences not yet in the OEIS.
LINKS
N. J. A. Sloane and Brady Haran, The Trapped Knight, Numberphile video (2019).
CROSSREFS
Sequence in context: A362027 A358150 A335214 * A330008 A335844 A110409
KEYWORD
nonn,fini
AUTHOR
Andrew Smith, Oct 20 2020
STATUS
approved

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Last modified May 8 19:26 EDT 2024. Contains 372341 sequences. (Running on oeis4.)