Arithmetic Sequence
Find the nth term and sum of an arithmetic progression.
Your numbers
Nth term
Use consistent units. The result follows the assumptions you enter.
Scenario comparison
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Formula
aₙ=a₁+(n−1)d; Sₙ=n(2a₁+(n−1)d)/2
Find the nth term and sum of an arithmetic progression.
Worked example
- First term
- 3
- Common difference
- 2
- Number of terms
- 10
- Nth term
- 21
- Sum
- 120
Scope and limitations
Use consistent units. The result follows the assumptions you enter.
Inputs are checked for missing values and allowed ranges. A result outside the finite numeric range is not displayed. Rounding affects display, while the calculation uses the model’s numeric precision.
Check your units and assumptions before relying on a result. Changing a label does not convert a currency or physical unit.
Formula version: 61c72ad8b9e3 · Example checked: