Arithmetic Sequence Table: nth term by First term (a)
Reference table of nth term for Arithmetic Sequence across a range of first term (a) values — exact, engine-computed figures you can read off at a glance.
Arithmetic Sequence Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
nth term
29.0000
- Sum of first n terms
- 155.0000
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Arithmetic Sequence Calculator
The Arithmetic Sequence Calculator works out your nth term, along with 1 related figure in an instant. Enter first term (a), common difference (d) and term number (n) and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the first term (a).
- Enter the common difference (d).
- Enter the term number (n).
- Read off your nth term, together with sum of first n terms — the calculator updates automatically, with no button to press.
Formula
The Arithmetic Sequence Calculator uses the formula:
nth term = First term (a) + (Term number (n) - 1) × Common difference (d)
Worked example
For example, with first term (a) of 2, common difference (d) of 3 and term number (n) of 10, the nth term is 29.0000.
| First term (a) | 2 |
|---|---|
| Common difference (d) | 3 |
| Term number (n) | 10 |
| nth term | 29.0000 |
|---|---|
| Sum of first n terms | 155.0000 |
Results are estimates for educational use, not professional advice.
Frequently asked questions
It is a list of numbers where each term increases by a fixed amount, the common difference. Starting at 2 with a difference of 3 gives 2, 5, 8, 11, …
Use a + (n − 1) × d. The 10th term of the sequence starting at 2 with difference 3 is 2 + 9 × 3 = 29.
The sum of the first n terms is n ÷ 2 × (2a + (n − 1)d). For the first 10 terms above, the sum is 155.
Yes. A negative difference makes a decreasing sequence, such as 20, 17, 14, … with a difference of −3.
Enter the first term (a). Enter the common difference (d). Enter the term number (n). Read off your nth term, together with sum of first n terms — the calculator updates automatically, with no button to press.
Related guides
How to Calculate Arithmetic Sequence: Formula, Steps & Examples
Learn how to calculate Arithmetic Sequence — the formula explained step by step, with worked examples and a free calculator to check your answer.