An arithmetic sequence is a sequence of numbers such that the difference between the consecutive terms is constant. For instance, the sequence 5, 7, 9, 11, 13, 15 … is an arithmetic sequence with common difference of 2.
Wikipedia
In Wikipedia's example,
5 1st term
5+2 = 7 2nd term
7+2 = 9 3rd term
...
( )+2= ( ) nth term
...
Formula for the nth term,
a_{n}=a_{1}+(n1)(d)
a_{n} is the nth term
a_{1} is the first term
d is the difference
So in wikipedia's example,
a_{n}=a_{1}+(n1)(d)
a_{n} = 5+(n1)*2
Use your own numbers, and try to put the right parts into the formula.
3/19/2014

Eric Y.