For the mentioned family of pretzel knots (2p+1),(2q+1),-(2r+1)
D((2p+1),(2q+1),-(2r+1)) = 
pq-pr-qr-r+(-2pq+2pr+2qr+2r+1)t+(pq-pr-qr-r)t2,
and the Conway polynomial is
C((2p+1),(2q+1),-(2r+1)) = 1+(pq-pr-qr-r)x.
For pq = pr+qr+r it follows D = 1 and C = 1.

This points to the more general conclusion: for every family of KLs we can derive a general formula for Alexander polynomials, where the coefficients are expressed by numbers appearing in a Conway symbol of the KLs. Later we will see that the same holds for all polynomial invariants, but the formulas derived will be more complicated.

Before returning to that question and a series of similar questions about families and the regular distribution of KL invariants (as signatures, symmetry groups, chirality, unknotting and unlinking numbers, etc.) we will continue with the derivation of KLs in Conway notation. After that, we will be able to work with all KLs, and not just with the already derived rational KLs.

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