[seqfan] Re: Empirical relation for A180169: Sigma(A180162(n)), where A180162(n) is the smallest N such that sigma(N) is an nth power, or 0 if no such N can be found
Georgi Guninski
guninski at guninski.com
Fri Feb 25 17:25:31 CET 2011
Hello,
unfortunately almost the entire sequence is consecutive powers of 2...
(except for the few initial terms).
On Fri, Feb 25, 2011 at 04:59:32PM +0100, Simon Plouffe wrote:
>
> Hello,
>
> for A180169, I have this
> generating function :
>
> (-1-x+2560*x^5+93184*x^7-46592*x^6+725590016*x^12+2*x^2-1280*x^4-362795008*x^11)/(2*x-1),
>
>
> It has a score of 8.34 and it matches all the
> terms in the sequence.
>
> I checked the series and the 468'th term and they do match.
>
> I would say that this generating functions has good chances
> to be the good one.
>
> My I add it to the sequence formulas ?
>
> Best Regards,
>
> Simon Plouffe
>
>
>
>
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