Partition().to_exp() should return Sage Integers

Author: jdemeyer

src/sage/combinat/partition.py

@@ -3101,11 +3101,16 @@ def to_exp(self, k=0):
             [1, 2, 1]
             sage: Partition([3,2,2,1]).to_exp(5)
             [1, 2, 1, 0, 0]
+
+        TESTS::
+
+            sage: [parent(x) for x in Partition([3,2,2,1]).to_exp(5)]
+            [Integer Ring, Integer Ring, Integer Ring, Integer Ring, Integer Ring]
         """
         p = self
         if len(p) > 0:
             k = max(k, p[0])
-        a = [ 0 ] * (k)
+        a = [ZZ.zero()] * k
         for i in p:
             a[i-1] += 1
         return a