math
posted by Geo .
input 2,4 and 10 output 5,9 and 21 I do not get it at all please help me.

Input + 2n + 1 = Output

Sorry again but what does 2n mean. Thank you.

2n = 2 times n
(2 * 2) + 1 = 5
(4 * 2) + 1 = 9
(10 * 2) + 1 = 21 
output = 2 n + 1
if n = 2,
output = 2*2 + 1 = 5
if n = 10
output = 2*10 + 1 = 21 
Thank you Ms.Sue and Damon you guys really have helped me a lot.