What is the nth term of the sequence 2, 6, 12, 20…?

A.
4n – 2 
B.
2(3^{n – 1}) 
C.
n^{2} + n 
D.
n^{2} + 3n + 2
Correct Answer: Option C
Explanation
Given that 2, 6, 12, 20…? the nth term = n^{2} + n
check: n = 1, u_{1} = 2
n = 2, u_{2} = 4 + 2 = 6
n = 3, u_{3} = 9 + 3 = 12
∴ n = 4, u_{4} = 16 + 4 = 20