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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.
Formel
If n even: n → n/2; If n odd: n → 3n+1
- n
- positive integer — starting value for the sequence
- s
- stopping time — number of steps to reach 1
Trin-for-trin guide
- 1If n is even: next = n / 2
- 2If n is odd: next = 3n + 1
- 3Continue until reaching 1
- 4The number of steps is called the "stopping time"
Løste eksempler
Input
n = 6
Resultat
6 → 3 → 10 → 5 → 16 → 8 → 4 → 2 → 1 (8 steps)
Input
n = 27
Resultat
111 steps, reaches maximum of 9,232
Ofte stillede spørgsmål
Is the Collatz conjecture proven?
No, it remains one of mathematics' great unsolved problems despite being tested for numbers up to 2⁶⁸.
Why does the Collatz sequence sometimes increase dramatically?
Odd numbers multiply by 3, creating larger values. But many steps follow: divide by 2 repeatedly until odd again.
What is the longest known Collatz stopping time?
For starting values tested, stopping times are in the hundreds. 27 requires 111 steps.
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