Limits RegistryPUBLIC RECORD
Limits RegistryDavid Barína of Brno University of Technology verified that every starting value below 2^71 (about 2.36x10^21) eventually reaches 1, completed on 15 January 2025 and published in the Journal of Supercomputing. The project used GPU algorithms about 1,335 times faster than his first CPU version across several European supercomputers.
The question, scope, and sources behind this Registry record.
David Barína of Brno University of Technology verified that every starting value below 2^71 (about 2.36x10^21) eventually reaches 1, completed on 15 January 2025 and published in the Journal of Supercomputing. The project used GPU algorithms about 1,335 times faster than his first CPU version across several European supercomputers.
The largest N such that every positive integer below N has been verified by computation to reach 1 under iteration of the Collatz (3x+1) map.
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Current frontiers derived from accepted Claims.
An observed or demonstrated result; no opposing bound is implied.
The frontier is not sacred
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The frontier as it changed over time.
Only accepted Claims matching the current specification contribute to the displayed bounds. Strict inequalities remain open; contradictory Claims require editorial review.
1 accepted Claim, with 1 linked evidence records.
Permanent ID limitsregistry.com/limits/LR-COLLATZ-VERIFICATION-BOUND
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Limits Registry. LR-COLLATZ-VERIFICATION-BOUND. Largest bound to which the Collatz conjecture has been verified. 2026.