Fixed bugs in is_nthpow_residue

[erdOne]

Brief description of what is fixed or changed

is_nthpow_residue(a, n, m) returns False when a % m == 0 and primitive_root(m) is not None but it should return True.

Release Notes

• ntheory
  • Added check for zero in is_nthpow_residue.

[sympy-bot]

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• ntheory
  • Added check for zero in is_nthpow_residue. (#18129 by @erdOne)

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<!-- Your title above should be a short description of what
was changed. Do not include the issue number in the title. -->

#### Brief description of what is fixed or changed
`is_nthpow_residue(a, n, m)` returns `False` when `a % m == 0 and primitive_root(m) is not None` but it should return `True`.

#### Release Notes

<!-- Write the release notes for this release below. See
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<!-- BEGIN RELEASE NOTES -->
* ntheory
  * Added check for zero in is_nthpow_residue.
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

[jksuom]

There is (at least) one test that has to be fixed: assert is_nthpow_residue(2, 3, 2) is False intest_residue, otherwise this looks good.

[codecov]

Codecov Report

Merging #18129 into master will increase coverage by <.001%.
The diff coverage is 100%.

@@              Coverage Diff              @@
##            master    #18129       +/-   ##
=============================================
+ Coverage   74.933%   74.934%   +<.001%     
=============================================
  Files          642       642               
  Lines       166950    166970       +20     
  Branches     39275     39283        +8     
=============================================
+ Hits        125102    125118       +16     
+ Misses       36319     36313        -6     
- Partials      5529      5539       +10

[jksuom]

Thank you for your contribution.