Sum of the first 15 Even Numbers

Sum of the First <-- Enter n

Calculate the sum of the first 15 Even Numbers

Σ n Even Numbers formula:
S15 = n(n + 1)
S15 = 15(15 + 1)
S15 = 15(16)
S15 = 240

Display the first 15 Even Numbers where En denotes the nth number
n En
1 2
2 4
3 6
4 8
5 10
6 12
7 14
8 16
9 18
10 20
11 22
12 24
13 26
14 28
15 30