# [seqfan] Re: There are more terms in this sequence?

Charles Greathouse charles.greathouse at case.edu
Thu Feb 3 21:29:57 CET 2011

> The fourth term in the sequence is 148480, not 148840.

Good catch.

> There are no further terms up to 5 million.

No further terms to a billion; search to ten billion is in progress
but won't finish today.

Charles Greathouse
Analyst/Programmer
Case Western Reserve University

On Thu, Feb 3, 2011 at 3:07 PM, Harvey P. Dale <hpd1 at nyu.edu> wrote:
>        The fourth term in the sequence is 148480, not 148840.  There are no further terms up to 5 million.
>        This short Mathematica program will generate the sequence:
> Select[Range[5000000],MemberQ[Accumulate[Divisors[#]^2],#]&]
> If anyone wants to try to extend the sequence, changing the "Range" to, for example, [5000001,10000000] would check the next 5 million numbers.
>        Best,
>        Harvey
>
> -----Original Message-----
> From: seqfan-bounces at list.seqfan.eu [mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of Benoît Jubin
> Sent: Thursday, February 03, 2011 2:46 PM
> To: Sequence Fanatics Discussion list
> Subject: [seqfan] Re: There are more terms in this sequence?
>
> 0 is the sum of (the squares of) its first k divisors for two
> different values of k (0 and 1): these are two good reasons to include
> it in the sequence !
>
> Benoit
>
> On Thu, Feb 3, 2011 at 11:37 AM, Hans Havermann <pxp at rogers.com> wrote:
>> Andrew Weimholt:
>>
>>> Also, should we start with 0, since 0 is the sum of its first 0 divisors?
>>
>> I dunno. If a number has no divisors, then there is no sum (empty, not
>> zero).
>>
>> Claudio Meller:
>>
>>> 1, 130, 1860, 148840, 3039520
>>
>> a(4) = 148480
>>
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