Editing Harmonic divisor number (section)

{{Short description|Positive integer whose divisors have a harmonic mean that is an integer}}
{{About|harmonic divisor numbers|meanings of harmonic number|harmonic number (disambiguation)}}

In [[mathematics]], a '''harmonic divisor number''' or '''Ore number''' is a positive [[integer]] whose [[divisor]]s have a [[harmonic mean]] that is an integer. The first few harmonic divisor numbers are
:[[1 (number)|1]], [[6 (number)|6]], [[28 (number)|28]], [[140 (number)|140]], [[270 (number)|270]], [[496 (number)|496]], 672, 1638, 2970, 6200, [[8128 (number)|8128]], 8190 {{OEIS|id=A001599}}.
Harmonic divisor numbers were introduced by [[Øystein Ore]], who showed that every [[perfect number]] is a harmonic divisor number and conjectured that there are no odd harmonic divisor numbers other than 1.