Comment by zone411

Off-topic, but collatz(x) == 1 for all positive 64-bit integers (actually, this has been verified up to 2^71: https://link.springer.com/article/10.1007/s11227-025-07337-0). I recently made this tool if anyone wants to try it with 1,000-digit integers or ranges: https://www.proofatlas.ai/explore/collatz/.