A375209 Number of simple symmetric Hamiltonian paths connecting opposite corners of a 2n+1 X 2n+1 grid.
1, 2, 16, 564, 93866, 72054120, 260324223938, 4400423201461008, 349815282628284276844, 130501147375292529852604266, 228964256366276749773274186140858
Offset: 0
Examples
a(2) = 16, see link "Illustration".
Links
- Nicolay Avilov, Problem 2718. Broken Routes (in Russian).
- Nicolay Avilov, Illustration for term a(2)
Formula
a(n) = 2*A331001(2*n + 1) for n > 0. - Andrew Howroyd, Oct 16 2024
Extensions
Thanks to Suleiman Makarenko.
a(5)-a(10) from Andrew Howroyd, Oct 16 2024