A103931 Denominators of squares of harmonic numbers A001008/A002805.

1, 4, 36, 144, 3600, 400, 19600, 78400, 6350400, 6350400, 768398400, 768398400, 129859329600, 129859329600, 129859329600, 519437318400, 150117385017600, 16679709446400, 6021375110150400, 240855004406016, 26761667156224

Offset: 1

Author

Wolfdieter Lang, Mar 24 2005

Keywords

• nonn
• easy
• frac

Comments

The corresponding numerators are given in A103930. For the rational see the link there.

Programs

Mathematica

Denominator[HarmonicNumber[Range[30]]^2] (* Harvey P. Dale, Oct 16 2022 *)

Formula

a(n)=denominator(H(n)^2), with the harmonic numbers H(n)=A001008(n)/A002805(n), n>=1.