Collatz conjecture calculator

Result

Result

27 reaches 1 after 111 steps

Key figures of the sequence

Figure	Value
Steps to reach 1	111
Highest value in the sequence	9,232
reached at step	77
Halvings (even numbers)	70
3n+1 steps (odd numbers)	41
Steps until the sequence drops below the start	96

The sequence

27 → 82 → 41 → 124 → 62 → 31 → 94 → 47 → 142 → 71 → 214 → 107 → 322 → 161 → 484 → 242 → 121 → 364 → 182 → 91 → 274 → 137 → 412 → 206 → 103 → 310 → 155 → 466 → 233 → 700 → 350 → 175 → 526 → 263 → 790 → 395 → 1,186 → 593 → 1,780 → 890 → 445 → 1,336 → 668 → 334 → 167 → 502 → 251 → 754 → 377 → 1,132 → 566 → 283 → 850 → 425 → 1,276 → 638 → 319 → 958 → 479 → 1,438 → 719 → 2,158 → 1,079 → 3,238 → 1,619 → 4,858 → 2,429 → 7,288 → 3,644 → 1,822 → 911 → 2,734 → 1,367 → 4,102 → 2,051 → 6,154 → 3,077 → 9,232 → 4,616 → 2,308 → 1,154 → 577 → 1,732 → 866 → 433 → 1,300 → 650 → 325 → 976 → 488 → 244 → 122 → 61 → 184 → 92 → 46 → 23 → 70 → 35 → 106 → 53 → 160 → 80 → 40 → 20 → 10 → 5 → 16 → 8 → 4 → 2 → 1

Longest sequences up to the limit

Starting number	Steps
6,171	261
9,257	259
6,943	256
7,963	251
8,959	246

It is not proven that every sequence reaches 1 – computers have checked all starting numbers up to about 2.95 · 10²⁰.