Prime Circle
A prime circle of order
is a free circular permutation of the numbers
from 1 to
with adjacent pairs summing to a prime,
where
is a positive integer. Rotations
and reflections of an arrangement are counted as equivalent.
The numbers of prime circles for
, 2, ..., are 1, 1, 1, 2, 48, 512, ... (OEIS A051252).
The prime circles for the first few even orders are given in the table below.
| prime circles | |
| 2 | |
| 4 | |
| 6 | |
| 8 |
See also
Circular PermutationExplore with Wolfram|Alpha
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.Sloane, N. J. A. Sequence A051252 in "The On-Line Encyclopedia of Integer Sequences."Referenced on Wolfram|Alpha
Prime CircleCite this as:
Weisstein, Eric W. "Prime Circle." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/PrimeCircle.html