diff --git a/src/sage/combinat/rigged_configurations/rigged_configuration_element.py b/src/sage/combinat/rigged_configurations/rigged_configuration_element.py
index 78614e52df1..50992a59dd7 100644
--- a/src/sage/combinat/rigged_configurations/rigged_configuration_element.py
+++ b/src/sage/combinat/rigged_configurations/rigged_configuration_element.py
@@ -597,7 +597,7 @@ def e(self, a):
             else:
                 # Update the vacancy numbers and the rigging
                 for i in range(len(new_vac_nums)):
-                    if new_list[i] < k:
+                    if k is not None and new_list[i] < k:
                         break
 
                     new_vac_nums[i] += M[a,b]
@@ -651,7 +651,7 @@ def _generate_partition_e(self, a, b, k):
         # Update the vacancy numbers and the rigging
         value = self.parent()._cartan_matrix[b,a]
         for i in range(len(new_vac_nums)):
-            if new_list[i] < k:
+            if k is not None and new_list[i] < k:
                 break
 
             new_vac_nums[i] += value
diff --git a/src/sage/combinat/rigged_configurations/rigged_partition.pyx b/src/sage/combinat/rigged_configurations/rigged_partition.pyx
index 47a91f3f174..9399c042707 100644
--- a/src/sage/combinat/rigged_configurations/rigged_partition.pyx
+++ b/src/sage/combinat/rigged_configurations/rigged_partition.pyx
@@ -143,7 +143,7 @@ cdef class RiggedPartition(SageObject):
         ret_str = ""
         vac_num_width = max(len(str(vac_num)) for vac_num in self.vacancy_numbers)
         for i, val in itr:
-            ret_str += ("{:>" + str(vac_num_width) + "}").format(self.vacancy_numbers[i])
+            ret_str += ("{:>" + str(vac_num_width) + "}").format(str(self.vacancy_numbers[i]))
             ret_str += "[ ]"*val
             ret_str += str(self.rigging[i])
             ret_str += "\n"