on.
n : int
   where ``n >= 0``; the degree of the Legendre function.  Often
   called ``l`` (lower case L) in descriptions of the associated
   Legendre function
z : array_like
    Input value.

Returns
-------
Pmn_z : (m+1, n+1) array
   Values for all orders 0..m and degrees 0..n
Pmn_d_z : (m+1, n+1) array
   Derivatives for all orders 0..m and degrees 0..n

See Also
--------
clpmn: associated Legendre functions of the first kind for complex z

Notes
-----
In the interval (-1, 1), Ferrer's function of the first kind is
returned. The phase convention used for the intervals (1, inf)
and (-inf, -1) is such that the result is always real.

References
----------
.. [1] Zhang, Shanjie and Jin, Jianming. "Computation of Special
       Functions", John Wiley and Sons, 1996.
       https://people.sc.fsu.edu/~jburkardt/f77_src/special_functions/special_functions.html
.. [2] NIST Digital Library of Mathematical Functions
       https://dlmf.nist.gov/14.3

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