Sequence to consider

[David Wilson]

I'm almost ashamed to admit it but,

I was under the mistaken impression that sigma(n) was odd only for square n, 
this is in fact a property of d(n). Therefore, in my first posting, I looked 
only for values of sigma(k^2), thus missing the smaller values found by 
T.D.Noe.

----- Original Message ----- 
From: "T. D. Noe" <noe at sspectra.com>
To: "Jack Brennen" <jb at brennen.net>; "Sequence Fans" <seqfan at ext.jussieu.fr>
Cc: "Max A." <maxale at gmail.com>; "David Wilson" <davidwwilson at comcast.net>
Sent: Monday, October 02, 2006 12:28 PM
Subject: Re: Sequence to consider


> At 10:55 AM -0700 9/30/06, T. D. Noe wrote:
>>At 10:19 AM -0700 9/30/06, T. D. Noe wrote:
>>>>Smallest odd number A such that sigma(x)=A has n solutions.
>>>>
>>>>So:  sigma(16)=31 and sigma(25)=31.
>>>>
>>>
>>>I think the sequence begins 1, 31, 347529, 10773399
>>>
>>>The 3 numbers with sigma(k)=347529 are 164836, 203522, 239121
>>>
>>>The 4 numbers with sigma(k)=10773399 are 3825936, 4120900, 5088050, 
>>>5978025
>>
>>More terms:
>>
>>1, 31, 347529, 10773399, 4104665019, 77253471477, 28732655133
>
> I just submitted this sequence as A123523 (Smallest odd number k such that
> sigma(x)=k has exactly n solutions).  If anyone has more terms, please
> update this sequence.
>
> Tony
>
>
>
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