[seqfan] Re: What is a "Q unit fraction"?

Neil Sloane njasloane at gmail.com
Sat Dec 22 21:18:07 CET 2018

I will ask Bob Wilson directly

In the mean time I added "obsc" (to A016013).

Q is pretty certainly a numerical value (or range), since A016017 is
%N A016017 Smallest k such that 1/k can be written as a sum of exactly 2
unit fractions in n ways.
and - also from Bob Wilson  - there is:
%N A018892 Number of ways to write 1/n as a sum of exactly 2 unit fractions.

Best regards

Neil J. A. Sloane, President, OEIS Foundation.
11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
Phone: 732 828 6098; home page: http://NeilSloane.com
Email: njasloane at gmail.com

On Sat, Dec 22, 2018 at 2:46 PM Alex Meiburg <timeroot.alex at gmail.com>

> Two guesses. First option: this is a "q-analog" of a unit fraction. There
> are "q-analogs" of a variety of quantities, but I don't understand them
> very well and I think you'd have to specify q? Maybe it ends up being
> independent of q here, though.
> Second option: you're misparsing the description, and instead of
> decomposing into "Q unit fractions", it's decomposing into plain old unit
> fractions, of which there are Q. Q is some variable that hasn't been
> properly explained.
> Actually, I'd bet on the second one, given that they say "exactly Q" unit
> fractions, which really suggests that Q is a quantity of unit fractions.
> On Sat, Dec 22, 2018, 11:30 AM Sean A. Irvine <sairvin at gmail.com wrote:
> > A016013 Number of ways to write 1/n as a sum of exactly Q unit fractions.
> >
> > Not a lot of information to go on here.
> >
> > Sean.
> >
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> >
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