# Thread: The term of Number

1. ## The term of Number

Could you help me to solve this :

What is the 60th term of 23, -16, 9, -2, -5, 12, -19,...?

2. ## Re: The term of Number

Originally Posted by AlvaJr
Could you help me to solve this :

What is the 60th term of 23, -16, 9, -2, -5, 12, -19,...?
the recurrence relation is

$a_n=-(a_{n-1}+7 (-1)^n)$

$a_1=23$

you can dump this into excel or go to wolframalpha.com to find the 60th term.

3. ## Re: The term of Number

Nio need to use Excel or any other fancy tool. The even numbered terms have the sequence -16, -2, 12, ... Note that each even term is 14 greater than the preceeding even term. Hence the 60th term in the sequence, which is the 30th even term, will have the value: -16 + (29x14).