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Number sequence calculator

Find a term, partial sum, and downloadable list for arithmetic, geometric, or Fibonacci sequences.

Get started

  1. Use the example values or enter your own measurements.
  2. Calculate, then copy the result or download the available details.

Example

Input

Arithmetic sequence, first 7, difference −3, index 8

Expected result

−14, sum −28

Try it

Good to know

The calculation runs in your browser. Use consistent units in fields with no explicit unit.

Calculation method

Arithmetic and geometric indices start at 1. Fibonacci starts at F₀ = 0. The Fibonacci list uses exact integers.

an=a1+(n−1)d,gn=g1rn−1,Fn=Fn−1+Fn−2a_n=a_1+(n-1)d,\quad g_n=g_1r^{n-1},\quad F_n=F_{n-1}+F_{n-2}

Calculation mode

Arithmetic
  • First term
  • Common difference
  • Index
Geometric
  • First term
  • Common ratio
  • Index
Fibonacci
  • Index