Collatz sequence

Client

Follow the 3n+1 rule until you hit 1—useful for exploring the Collatz conjecture with small integers.

About Collatz sequence

Generate the 3n+1 Collatz sequence from a starting integer until it reaches 1—local BigInt steps. The interactive transform on this page runs in your browser tab—Toolcore does not need your paste for the core operation described above.

How to use this page

Paste or type in the main workspace, run the primary action from the toolbar, then copy or download the result. Use Load example when the page offers it, or URL prefill (?q= / ?qb=) so agents and tickets open the same input.

8 steps to reach 1

6 → 3 → 10 → 5 → 16 → 8 → 4 → 2 → 1

Nearby workflows on Toolcore

  • Fibonacci sequence generator — Generate the first n Fibonacci numbers (0, 1, 1, 2, …) locally—up to 500 terms. when units or numeric output should be checked on a related calculator.
  • Prime number checker — Test whether a whole number is prime—BigInt trial division in your browser, no upload. when units or numeric output should be checked on a related calculator.
  • Math expression evaluator — Evaluate basic + − × ÷ arithmetic with parentheses in your browser—no variables. when units or numeric output should be checked on a related calculator.
  • Digit sum — Sum the decimal digits of a whole number—local arithmetic for puzzles and divisibility checks. when units or numeric output should be checked on a related calculator.

Common use cases

  • Visualize Collatz steps for homework or curiosity.
  • Compare step counts for nearby starting values.

Common mistakes to avoid

  • Starting at 0

    The classic sequence begins from a positive integer.

FAQ

Does every number reach 1?

The Collatz conjecture says yes—it is unproven for all integers.

Is data uploaded?

No. The sequence is computed locally.

More tools

Related utilities you can open in another tab—mostly client-side.