Question

Find the 31st term of the following sequence.

9, 15, 21

Answer 1

First you have to make a algebraic expression to go with the term to term number.

The algebraic expression that goes with this is X6+3

Term 1 from transfer to 9:1X6+3=9

Term 2 from transfer to 15:2X6+3=15

Term 3 from transfer to 21:3X6+3=21

So, 31X6+3= 189

Answer 2

Hello,

You should have said that the sequence was arithmetic!!
(there are at least 225 results found. at OEIS)


a(n)=3+(n-1)*6
a(31)=3+30*6=189