Number Sequence Calculator

Enter a list of numbers to detect whether they follow an arithmetic or geometric pattern, and predict the next term.

  • Free to use
  • Accurate results
  • No registration required
  • Works on all devices
Enter a list of numbers to detect whether they form an arithmetic or geometric sequence and predict the next term.
Enter at least 3 numbers, in order, separated by commas or spaces.

Your result

14

Predicted next term

Pattern detectedarithmetic
Common difference or ratio3

AI explanation

Formula

Checks for a constant difference between consecutive terms (arithmetic), then a constant ratio (geometric)

Worked example

2, 5, 8, 11

Worked example: 2, 5, 8, 11
FieldValue
Numbers2, 5, 8, 11
Pattern detectedarithmetic
Common difference or ratio3
Predicted next term14

Assumptions

  • Only detects simple arithmetic (constant difference) or geometric (constant ratio) patterns — more complex patterns (like perfect squares or a mix of rules) are reported as "unknown".
  • Geometric detection is skipped if any entered number is zero, since a ratio involving zero is either undefined or degenerate.

Frequently asked questions

How does this calculator detect the pattern?

It first checks whether the difference between every consecutive pair of numbers is the same (arithmetic). If not, it checks whether the ratio between every consecutive pair is the same (geometric). If neither holds, it reports the pattern as unknown.

What if my sequence isn't purely arithmetic or geometric?

This calculator only detects those two simple patterns. Sequences based on squares, cubes, alternating rules, or other patterns will show "unknown" — you'd need to identify the rule manually or use a specialized tool.

How many numbers should I enter?

At least 3, so the calculator can verify the pattern holds across more than one pair of terms. More terms give higher confidence that the detected pattern is genuinely consistent.

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