OFFSET
1,2
COMMENTS
The grid is numbered as follows:
1: [0, 0, 0]
-- 1 step --
2: [0, 0, 1]
3: [0, 1, 0]
4: [1, 0, 0]
-- 2 steps --
5: [0, 0, 2]
6: [0, 1, 1]
7: [0, 2, 0]
8: [1, 0, 1]
9: [1, 1, 0]
10: [2, 0, 0]
etc.
EXAMPLE
1: [0, 0, 0] is an odd cell, hence a double move is required. Since 5: [0, 0, 2] and 7: [0, 2, 0] are also odd, 10: [2, 0, 0] is the only valid move.
The sequence ends at 16: [1, 1, 1]. A single move is required, which limits the possible destination cells to:
6: [0, 1, 1], even;
8: [1, 0, 1], even;
9: [1, 1, 0], already visited;
27: [1, 1, 2], already visited;
28: [1, 2, 1], even;
31: [2, 1, 1], already visited;
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
Jan Koornstra, Apr 02 2019
STATUS
approved