Sequence Calculator

Arithmetic and geometric sequences — nth term and sum.

Term 10
48
Sum of first n
255
Common difference
5
First 5 terms
3, 8, 13, 18, 23
Show the working
  1. 1aₙ = a₁ + (n−1)d = 3 + 9×5 = 48
  2. 2Sum = n/2 × (2a₁ + (n−1)d) = 255
Formula
arithmetic aₙ = a₁ + (n−1)d; geometric aₙ = a₁rⁿ⁻¹

How it works

The nth term and running sum of an arithmetic or geometric sequence.

Example

The arithmetic sequence 3, 8, 13, … has a 10th term of 48 and sums to 255.

About the Sequence Calculator

Arithmetic and geometric sequences — nth term and sum. It sits in the Math & Algebra section of NWS Calc, a free collection of calculators that run entirely in your browser. There is no signup, no paywall and no tracking — open the page, enter your numbers, get an answer.

Frequently asked questions

Is the Sequence Calculator free to use?
Yes. Every calculator on NWS Calc is completely free, with no signup, no usage limits and no ads.
Does my data leave my device?
No. The Sequence Calculator runs entirely in your browser using JavaScript. Nothing you type is uploaded, logged or stored on a server.
Can I use the Sequence Calculator on my phone?
Yes. The page is fully responsive and works in any modern mobile or desktop browser — there is nothing to install.
What else is in Math & Algebra?
Equations, fractions, primes, roots, sequences and number theory. You can browse the full Math & Algebra category for related calculators.

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