diff --git a/src/chemfiles/residue.py b/src/chemfiles/residue.py
index 75ff1dc..869a6c6 100644
--- a/src/chemfiles/residue.py
+++ b/src/chemfiles/residue.py
@@ -55,7 +55,7 @@ def __iter__(self):
             yield self[i]
 
     def __repr__(self):
-        return "[" + ", ".join([i.__repr__() for i in self]) + "]"
+        return "[" + ", ".join([str(int(i)) for i in self]) + "]"
 
     def append(self, atom):
         """Add the atom index ``atom`` in the :py:class:`Residue`."""
diff --git a/tests/residue.py b/tests/residue.py
index 57ff8fe..8595c32 100644
--- a/tests/residue.py
+++ b/tests/residue.py
@@ -1,7 +1,6 @@
 import copy
 import unittest
 
-import numpy as np
 from _utils import remove_warnings
 
 from chemfiles import ChemfilesError, Residue