[seqfan] Re: The Sequencer OEIS survey

Max Alekseyev maxale at gmail.com
Wed Apr 15 00:43:42 CEST 2015


On Mon, Apr 13, 2015 at 3:00 AM, <hv at crypt.org> wrote:

>
> However the conjecture for A129254 will match little more than the values
> listed - the pattern will break as soon as we start to reach [neighbours
> of]
> multiples of 5^5, 3124 being the first example.
>

By similar reasons, the conjectured formula for A218564 (Numbers n such
that n2+1 is divisible by a 5th power) is wrong.
The "period" in the conjectured formula is 5^5, and the listed sequence
terms just not yet reached the next possible fifth power divisor, which is
13^5.
E.g., there is a term 143044 of A218564 (with 143044^2 + 1 divisible by
13^5), which does not fit the proposed formula.

Regards,
Max


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