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Collatz Sequence Calculator

Generate the Collatz sequence for any starting number

Collatz Sequence Calculator

Starting Number (positive integer ≤ 1,000,000)

The Collatz conjecture states that for any positive integer, repeatedly applying the rule: if even divide by 2, if odd multiply by 3 and add 1 — will always eventually reach 1. It remains one of mathematics' most famous unsolved problems.

  1. 1If n is even: next = n / 2
  2. 2If n is odd: next = 3n + 1
  3. 3Continue until reaching 1
  4. 4The number of steps is called the "stopping time"
n = 6=6 → 3 → 10 → 5 → 16 → 8 → 4 → 2 → 1 (8 steps)
n = 27=111 steps, reaches maximum of 9,232
Starting nSteps to 1Maximum reached
6816
111452
271119232
10025200
100011113120
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