A237431 Number of nonisomorphic Hamiltonian cycles on 2n X 2n square grid of points with exactly two axes of reflective symmetry.

0, 1, 3, 20, 244, 6891, 378813, 47917598, 12118420172, 6998287399637

Offset: 1

Author

Ed Wynn, Feb 07 2014

Keywords

• nonn
• walk
• more

Examples

			Examples of 2 of the 3 classes for n=3. Note that all examples also have two-fold (but not four-fold) rotational symmetry.
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Links

• Ed Wynn, Enumeration of nonisomorphic Hamiltonian cycles on square grid graphs, arXiv:1402.0545 [math.CO], 2014.

Crossrefs

Cf. A209077, A227005, A237432.