diff --git a/pandas/core/window.py b/pandas/core/window.py
index f332075380c79..ab1f49aec2ad1 100644
--- a/pandas/core/window.py
+++ b/pandas/core/window.py
@@ -530,8 +530,8 @@ class Window(_Window):
     >>> df.rolling(2, win_type='triang').sum()
          B
     0  NaN
-    1  1.0
-    2  2.5
+    1  0.5
+    2  1.5
     3  NaN
     4  NaN