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

[Andrew Weimholt]

I haven't the time to look for more terms, but I see no obvious reason to expect
this sequence to be finite.

As for the title, how about the following?
Numbers equal to the sum of the squares of their first k divisors, for some k.

You should also include a separate sequence for the k values:
1, 4, 11, 19, 31, ...(if I've counted correctly)

Also, should we start with 0, since 0 is the sum of its first 0 divisors?
I'm not sure - maybe other seqfans can weigh in on this question.

Andrew


On 2/3/11, Claudio Meller <claudiomeller at gmail.com> wrote:
> There are more terms in this sequence?
> Is good the title ?
>
> Numbers that are equal to the sum of the squares of his first divisors
>
> 1, 130, 1860, 148840, 3039520
>
> 130 (1, 2, 5, 10) 1^2+2^2+5^2+10^2 = 1+4+25+100 = 130
>
> 1860 (1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30)
>
> 148480 (1, 2, 4, 5, 8, 10, 16, 20, 29, 32, 40, 58, 64, 80, 116, 128, 145,
> 160, 232)
>
> 3039520 (1, 2, 4, 5, 8, 10, 11, 16, 20, 22, 32, 40, 44, 55, 80, 88, 110
> 121, 157, 160, 176, 220, 242, 314, 352, 440, 484, 605, 628, 785, 880) 121,
> 157, 160, 176, 220, 242, 314, 352, 440, 484, 605, 628, 785, 880)
>
> Thanks,
> Claudio
>
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