[seqfan] Re: sigma(n) < min(sigma(n-1),sigma(n+1)), n=10*m?

zak seidov zakseidov at yahoo.com
Sun Oct 10 08:43:41 CEST 2010


> From: zak seidov <zakseidov at yahoo.com>
> Subject: [seqfan] Re: sigma(n) < min(sigma(n-1),sigma(n+1)), n=10*m?
> To: "Sequence Fanatics Discussion list" <seqfan at list.seqfan.eu>
> Date: Saturday, October 9, 2010, 5:56 AM
> 
> --- On Sat, 10/9/10, zak seidov <zakseidov at yahoo.com>
> wrote:
> 
> > From: zak seidov <zakseidov at yahoo.com>
> > Subject: [seqfan]  sigma(n) <
> min(sigma(n-1),sigma(n+1)), n=10*m?
> > To: "seqfaneu" <seqfan at seqfan.eu>
> > Date: Saturday, October 9, 2010, 5:53 AM
> > Dear seqfans,
> > 
> > What is the least n of the form n=10*m, such that 
> > 
> > sigma(n) < min(sigma(n-1),sigma(n+1))?
> > 
> > 
> > (That is, sigma(n) is the strict local minimum;
> > sigma(n) = A00203(n) )
> > 
> > First let's find at least one such n and then 
> > let's try to improve the limit!
> > 
> To start with, 
> Charles Greathous gave the example
> 
> n=5707019657504475216700242307626915459099744204108184475974056118653623493126356870
> 
> But this not the minimum for sure!
> 

The strong pretendent for the minimm is
(according to Yury Volvovskiy (and me:))

10899118150512092355662334281801606571010.

Anyone may wish to beat the record?

> > Thanks,
> > Zak



      




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