[seqfan] Re: Sequence related to A180919

Joerg Arndt arndt at jjj.de
Thu Jan 20 08:19:18 CET 2011


* Robert Israel <israel at math.ubc.ca> [Jan 20. 2011 08:05]:
> Maybe a "heavier-duty" number theorist would have written it this
> way:
> 
> use numtheory in
>  A := (n::posint) ->
>     if n = 1 then  0
>     elif n = 2 then infinity
>     elif n mod 4 = 0 then
>       tau(n^2/4 - 1)/2 -1
>     elif n mod 4 = 2 then
>       tau(n^2/16 - 1/4)/2 - 1
>     else
>       tau(n^2-4)/2 - 1
>     end if
>    end use;
> 

Now that's lovely, thank you!

> [...]

> >I don't know if we want "infinity" as the member of the sequence
> >for n=2, though.
> >

We can't for technical reasons  8-)
A remark should obviously be added.


> [...]

Again, thanks for you help,   jj



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