Hello There!
-3 1 4 9 13.
+4 +4 +4 +4
As you can see above, to get from one number to the next it is simply adding 4. So the formula is simply just x + 4.
Hope This Helps You!
<span>Good Luck :) </span>
<span>- Hannah ❤</span>
D D B I think this should be right