This is the Thistlethwaite name of the link. It is of the form L[k]a[j_{1}] or L[k]n[j_{1}],
depending on whether the link is alternating or not.
Here, k is the crossing number and j_{1}, j_{2}
are archive numbers assigned to each (a, k), (n, k) pair, respectively. For example, L5a1
is the first alternating link with 5 crossings while L6n2 is the second non-alternating link with 6 crossings.

**References**

[1] Hoste, J., Thistlethwaite, M., and Weeks, J. *The First 1,701,936 Knots*, Math. Intelligencer, 20 (1998), 33-48.