bibkey: cicuttin2017a152020 authors: Andres Cicuttin year: 2017 title: “OEIS A152020, Denominator of 8/(9n^2) divided by 9” doi: null url: https://oeis.org/A152020 claim: “Denominator of 8/(9n^2) divided by 9. a(n) = n^2/gcd(n^2, 8). - Andrew Howroyd, Jul 25 2018 Conjecture: a(n) = denominator((n-2)^3/n^2). - Andres Cicuttin, Sep 19 2017” strata_touched:

• D5/S3/Arith/Congruence/RationalDenominatorCubeShift license: citation-only triage: anchor

OEIS A152020

The entry names the sequence as the positive reduced denominator of 8/(9*n^2), divided by 9, with offset 1. Andrew Howroyd’s formula of July 25, 2018 identifies the terms as n^2/gcd(n^2, 8).

Andres Cicuttin’s formula of September 19, 2017 identifies the same terms with the positive reduced denominator of (n-2)^3/n^2. The formal definition uses Rat.den and natural-number division by 9. The theorem proves that this division is exact and gives Cicuttin’s denominator formula for every positive index.

Verified locator

• URL: https://oeis.org/A152020
• Locator: FORMULA: Conjecture: a(n) = denominator((n-2)^3/n^2). - Andres Cicuttin, Sep 19 2017