Sum of the First N Even Numbers
Print 2 + 4 + 6 + … (N terms).
Input: one integer N.
Output: N(N+1).
Constraints:
- 1 ≤ N ≤ 109
Sample Tests
Input 1
3
Output 1
12
Input 2
1
Output 2
2
Discussion (opens after you solve — no spoilers before)
No comments yet.