A link is said to be splittable if a plane can be embedded in such that the plane separates one
or more components of
from other components of and the plane is disjoint from . Otherwise, is said to be nonsplittable.

The numbers of nonsplittable links (either prime or composite) with , 1, ... crossings are 1, 0, 1, 1, 3, 4, 15, ... (OEIS A086826).

Finch, S. "Knots, Links, and Tangles." http://algo.inria.fr/bsolve/.Sloane, N. J. A. Sequence A086826 in "The
On-Line Encyclopedia of Integer Sequences."