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A396337
Number of directed self-avoiding paths in the mod n square grid graph, reduced for symmetry (with rotations, reflections, and translations not counted as distinct).
3
0, 4, 127, 11336, 2761827, 1891984647, 3720952049343
OFFSET
1,2
COMMENTS
Here a "mod n square grid graph" is a n X n graph with wrapping allowed, e.g., a path can make a 1 unit step between the left and the right edge (same row) or the top and the bottom edge (same column) of the graph.
Excludes 0 length paths; including them increases each term by 1.
EXAMPLE
a(2) = 4, all symmetric and count as 1 each both undirected and directed:
X--X X--+ X--+ X--+
| | |
X X--+ ..X +..
Nonsymmetric paths count as 2 each when directed, e.g.:
X--+--+ X>>+>>+ X<<+<<+
| -> v and ^
X X X
CROSSREFS
Cf. A395462 (undirected), A394066 (wrapping disallowed).
Sequence in context: A070781 A152421 A270959 * A291851 A128790 A267796
KEYWORD
nonn,walk,hard,more
AUTHOR
Charles L. Hohn, May 22 2026
STATUS
approved