Number Sequence Calculator

Arithmetic Sequences

In an arithmetic sequence, every term is found by adding the same fixed amount (the common difference, d) to the term before it. The nth term and the sum of the first n terms both have direct formulas so you don't need to add every term one by one.

Geometric Sequences

In a geometric sequence, every term is found by multiplying the term before it by the same fixed ratio (r). These sequences grow (or shrink) much faster than arithmetic ones once r moves away from 1.