Write an expression for the nth term of the sequence 4,24,124,624,....
A)
B)
C)
D)

Question

Write an expression for the ​nth term of the sequence 4,24,124,624,.... ​​
A) ​ 
B) ​ 
C) ​ 
D) ​

Quizplus · Accepted Answer

The sequence can be written as:
4×1
4×6
4×31
4×156
...
which can be expressed as:
4×(1, 6, 31, 156, ...) 
where (1, 6, 31, 156, ...) is the sequence of triangular numbers.
The nth term of the sequence of triangular numbers can be expressed as:
Tn = n(n+1)/2
Therefore, the nth term of the given sequence is:
an = 4×Tn = 2×n(n+1) 
So, the correct answer is option C, which shows the expression for the nth term: 11ea8970_6ab1_538a_861b_95cc72c3bdb2_TB1301_11.

Write an Expression for the ​Nth Term of the Sequence

Write an Expression for the Nth Term of the Sequence