[seqfan] RE : Re: Sum divides concatenation

[Eric Angelini]

Thanks to you too, Charles -- nice numbers!
Best,
E.



-------- Message d'origine--------
De: seqfan-bounces at list.seqfan.eu de la part de Charles Greathouse
Date: lun. 28/09/2009 19:23
À: Sequence Fanatics Discussion list
Objet : [seqfan] Re: Sum divides concatenation
 
It's not in the database.  The terms are
1, 2, 6, 250488, 19986, 118030, 133970, 693810, 2231328, 3407286,
5733260, 25176334, 75529002, ...

The next term is more than 100 million.  A good program could find
these values quickly, but I just used a few minutes of brute force.

Charles Greathouse
Analyst/Programmer
Case Western Reserve University

On Mon, Sep 28, 2009 at 12:35 PM, Jack Brennen <jfb at brennen.net> wrote:
> The next term would be 250488, if that's any help:
>
>   126250488 == (1+2+6+250488) * 504
>
> Eric Angelini wrote:
>> Hello SeqFans,
>> I don't know how to find more terms -- thus I don't know
>> if this is old hat in Neil's database:
>>
>> 1, 2, 6, ...
>>
>> The sum of the first n integers divides the concatanion of
>> the first n integers; always prolong the seq with the smal-
>> lest _natural_ number not yet used:
>>
>> 1 divides 1  --> HIT
>> 1+2   (=3) divides 12 --> HIT
>> 1+2+3 (=6) does not divide 123
>> 1+2+4 (=7) does not divide 124
>> 1+2+5 (=8) does not divide 125
>> 1+2+6 (=9) divides 126 --> HIT
>> etc.
>>
>> Best,
>> É.
>>
>>
>> _______________________________________________
>>
>> Seqfan Mailing list - http://list.seqfan.eu/
>>
>>
>
>
>
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