What number should replace the question mark:2, 6, 12, 20,
What number should replace the question mark:2, 6, 12, 20,
Explanation
1 x 1 + 1 = 2
2 x 2 + 2 = 6
3 x 3 + 3 = 12
4 x 4 + 4 = 20
5 x 5 + 5 = 30
6 x 6 + 6 = 42
1 x 1 + 1 = 2
2 x 2 + 2 = 6
3 x 3 + 3 = 12
4 x 4 + 4 = 20
5 x 5 + 5 = 30
6 x 6 + 6 = 42