5 second problem

Algebra Level 3

What is 1 + 3 + 5 + 7 + 9 + 11 + ..... + (n*2) - 1, in terms of n?

Like this problem if you solved it in less than 5 seconds.

2^n (n*(n+1)) * 3/2 4n /sqrt{n} n^2 n^4 (n*(n+1)) / 2 (n+1)(n-1)