A pretzel knot is formed from a planar unlink of two components by joining the two components with parallel twisted bands. For instance, P(2,5,-7) is formed by adding bands with 2, 5, and -7 half twists.
A Montesinos knot is formed in the same way, except the twists are replaced with rational tangles, and the knot is denoted M( p1/q1 , p2/q2 , .... ). Thus, P(2,5,-7) = M(2,5,-7).
As a basic example, the left handed (2,-5)-torus knot is the Montesinos knot M(1,1,1,1,1) = M(1/5).
Some times the notation isolates a single integer entry, M(n; p1/q1 , p2/q2 , .... ), which is the same knot as M(1/n, p1/q1, p2/q2 ...).
Castellano-Macías and Owad provided the data for 12 crossing knots. The algorithm is described in  which contains links to a posting of the data.
The data needs to be checked for orientations.
 Dunfield, N., "A table of boundary slopes of Montesinos knots Topology," 40 (2001), 309-315
 Hatcher, A. and Oertel, U., "Boundary slopes for Montesinos knots," Topology 28 (1989), 453-480.
 Castellano-Macías, F. and Owad, N., "The tunnel number of all 11 and 12 crossing alternating knots," arXiv preprint.