Arithmetic Sequence Calculator

Your details

Pick what you want to find. Fill in the fields that appear.
The starting value of the sequence.
The constant amount added to each term to get the next.
Which term to find, and how many terms to sum.
Display the first several terms as a scrollable table.
How many terms to show in the term list (max 100).
nth term (aₙ)
48
Sum of first n terms (Sₙ)255
Average of the terms25.5
nth term (aₙ)48
Sum (Sₙ)255

Term 10 equals 48, and the first 10 terms add up to 255.

  • Each term increases by 5 from the one before it.
  • The sum equals the term count times the average of the first and last term, a shortcut credited to Gauss.
  • The terms are evenly spaced, so their average is exactly the midpoint of the first and last term.

Next stepSwitch the solve mode to find a missing first term, common difference, or term count.

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