diff --git a/pyFTS/data/mackey_glass.py b/pyFTS/data/mackey_glass.py
index 9e5ee12..4b39055 100644
--- a/pyFTS/data/mackey_glass.py
+++ b/pyFTS/data/mackey_glass.py
@@ -17,7 +17,7 @@ def get_data(b=0.1, c=0.2, tau=17, initial_values = np.linspace(0.5,1.5, 18), it
     '''
     y = initial_values.tolist()
 
-    for n in np.arange(len(y), iterations+100):
+    for n in np.arange(len(y)-1, iterations+100):
         y.append(y[n] - b * y[n] + c * y[n - tau] / (1 + y[n - tau] ** 10))
 
-    return y[100:]
\ No newline at end of file
+    return y[100:]