We asked an unreleased research version of Claude to take a stab at the Riemann hypothesis. It…

TL;DR - Anthropic reports that an unreleased research version of Claude improved the known lower bound on the fraction of Riemann zeta zeros lying on the critical line from 41.6% to 67.2%, a concrete result on a problem adjacent to the Riemann hypothesis. It matters as a company-published data point on frontier models producing genuinely novel mathematical results rather than reproducing known ones.

• The model did not prove the Riemann hypothesis; it advanced a related quantitative result — the zero-density/critical-line lower bound.
• Reported improvement: 41.6% → 67.2% of zeros satisfying the hypothesis, a substantial jump on a long-studied bound.
• The work used an unreleased internal research version of Claude, so capabilities described are not available in shipped products.
• Framed by Anthropic as evidence about Claude's mathematical capabilities; details are in their linked research post, which is not included here, so verification of method and proof-checking is unavailable from this content alone.