Number Theory & Sequences

Arithmetic Sequence Term

Nth term of an arithmetic sequence.

aₙ = a₁ + (n−1)d

Variables

aₙ
nth term
a₁
first term
d
common difference

How to use this formula

Identify the known values, keep units consistent, substitute the values into the formula, and calculate carefully. Then check whether the result is reasonable for the original problem.