Calculate the nth term and the sum of the first n terms of a geometric sequence.
| aₙ | – |
| Sum | – |
Use this calculator for a sequence with a constant ratio r: 2, 6, 18, 54, … The nth term is aₙ = a₁ × r^(n−1). The sum is Sₙ = a₁ (1 − r^n) / (1 − r) when r ≠ 1, and Sₙ = a₁ × n when r = 1.
n must be a positive integer. r may be negative (alternating signs) or a fraction (a shrinking sequence). Large |r| and n can overflow.
First term a₁: The first term.
Common ratio r: Factor multiplied each step.
n: Which term and how many terms to sum (n ≥ 1).
aₙ: The nth term.
Sum: Sₙ, the sum of the first n terms.
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