A366778 Number of nonequivalent cycles of length 2n in the (2n+1) X (2n+1) knight graph.
3, 25, 480, 12000, 350256, 10780549, 344680960
Offset: 2
Examples
For n=2 the a(2)=3 solutions (in standard chess notation) are: (a1, c2, d4, b3), (a2, c1, d2, c3), and (a2, c1, d3, b3). Note that each of these three cycles is non-self-intersecting. For the remaining values of n there are two kind of cycles - self-intersecting and non-self-intersecting. For example, a self-intersecting cycle of length 6 is (a1, c2, b4, a2, c1, b3), while the cycle (a1, c2, e1, f3, d4, b3) is non-self-intersecting.
Links
- Stoyan Kapralov, Valentin Bakoev, and Kaloyan Kapralov, Algorithms for Construction and Enumeration of Closed Knight's Paths, Mathematics and Informatics, 2, (2023), 107-114; arXiv:2304.00565 [math.CO], 2023.
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