bibkey: oeis2026a394757 authors: OEIS Foundation Inc. year: 2026 title: OEIS A394757 doi: null url: https://oeis.org/A394757 claim: OEIS A394757 records the twin-prime center sequence whose terms satisfy the prime sigma-gcd condition and states that all terms are divisible by 18. strata_touched:

• D5/S3/Factorization/TwinPrimeSigmaGcdDivisibility license: citation-only triage: anchor

OEIS A394757

The OEIS entry defines the sequence using twin-prime centers k for which gcd(k, sigma(k)) is prime, and records the divisibility assertion addressed by the Lean module. The formal theorem uses the corresponding natural-number definition and supplies a proof for every k.

Verified locator

• URL: https://oeis.org/A394757