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Sequence Calculator

Find the nth term aₙ and the sum of the first n terms Sₙ for arithmetic and geometric sequences — with a term-by-term preview and full step-by-step working.

Arithmetic:  aₙ = a₁ + (n−1)d  ·  Geometric:  aₙ = a₁·r(n−1)
first term a₁ difference d term n

Enter the first term, the common difference d (arithmetic) or ratio r (geometric), and the term count n (a positive whole number).

Results

nth term aₙ
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Sum of first n terms — Sₙ
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Common difference d
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First terms preview
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Step-by-step