[seqfan] Re: A153025 5,235,72335

David Wilson davidwwilson at comcast.net
Wed Jan 21 00:57:02 CET 2009


Finally got some time to attend to this.

Here is the edited sequence in full:

%I A153025
%S A153025 5,235,72335
%N A153025 Numbers n with property that n and n^2 use only prime digits.
%C A153025 Probably finite. No other elements up to 10^40.
%e A153025 {5, 235, 72335}^2 = {25, 55225, 5232352225}
%K A153025 nonn,bref
%O A153025 1,1
%A A153025 Zak Seidov (zakseidov(AT)yahoo.com), Dec 17 2008


----- Original Message ----- 
From: "zak seidov" <zakseidov at yahoo.com>
To: "Sequence Fanatics Discussion list" <seqfan at list.seqfan.eu>
Sent: Thursday, December 18, 2008 11:19 AM
Subject: [seqfan] Re: A153025 5,235,72335


> Dear David,
>
> in case A153025'll appear in OEIS,
> could you plz edit it (remove "full, fini", add your result(s), etc).
>
> thx, zak
>
> --- On Thu, 12/18/08, David Wilson <dwilson at gambitcomm.com> wrote:
>
>> From: David Wilson <dwilson at gambitcomm.com>
>> Subject: [seqfan] Re: A153025 5,235,72335
>> To: "Sequence Fanatics Discussion list" <seqfan at list.seqfan.eu>
>> Date: Thursday, December 18, 2008, 10:34 AM
>> Yes, this is correct. We cannot prove the sequence is finite
>> by the
>> techniques thus far presented.
>>
>> What we can say:
>>
>> If my last program was correct, there are no other elements
>> <= 10^26.
>>
>> Under reasonable assumptions about the distribution of
>> digits in large
>> square numbers, the sequence is finite with probability 1
>> and the
>> likelihood of finding further elements is remote.
>>
>> f.firoozbakht at sci.ui.ac.ir wrote:
>> > Dear seqfans,
>> >
>> >  From discussion in seqfan list we don't conclude
>> that there are no
>> > other such numbers. So we don't know sequence is
>> full and finite.
>> > Am I right?
>> >
>> > Farideh
>
>
>
>
>
>
> _______________________________________________
>
> Seqfan Mailing list - http://list.seqfan.eu/


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