diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index e63774c..4a405d9 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -660,7 +660,12 @@ function forum_block_info() {
  * Implements hook_block_configure().
  */
 function forum_block_configure($delta = '') {
-  $form['block_num_' . $delta] = array('#type' => 'select', '#title' => t('Number of topics'), '#default_value' => config('forum.settings')->get('block.num_' . $delta), '#options' => drupal_map_assoc(array(2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)));
+  $form['block_num_' . $delta] = array(
+    '#type' => 'select',
+    '#title' => t('Number of topics'),
+    '#default_value' => config('forum.settings')->get('block.num_' . $delta),
+    '#options' => drupal_map_assoc(range(2, 20)),
+  );
   return $form;
 }