Arithmetic Sequence Calculator
Find the nth term and sum of an arithmetic sequence.
A sequence where each term increases by a fixed amount.
The math behind it
nth term = a₁ + (n−1)×d. Sum of first n terms = n × (first + last) ÷ 2.
Worked example
2, 5, 8, … 10th term = 29, sum = 155.
FAQ
Negative d?
Then the sequence decreases each step.