A prime circle of order is a Circular Permutation of the numbers from 1 to with adjacent Pairs summing to a Prime. The number of prime circles for , 2, ..., are 1, 1, 1, 2, 48, ....
References
Filz, A. ``Problem 1046.'' J. Recr. Math. 14, 64, 1982.
Filz, A. ``Problem 1046.'' J. Recr. Math. 15, 71, 1983.
Guy, R. K. Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, pp. 105-106, 1994.