[seqfan] Re: n and n^2 use digits 0, 1, 4, 6 only: A136859 - a question

[Bob Selcoe]

Hi Neil and seqfans,

Don't have time to investigate the conjecture (though at first glance I 
would suspect it's correct); but one simple point: shouldn't the title be 
numbers a(n) and a(n)^2...  to avoid confusion with conventional indexing 
for n?

Cheers,
Bob

--------------------------------------------------
From: "Neil Sloane" <njasloane at gmail.com>
Sent: Friday, January 29, 2016 5:35 AM
To: "Sequence Fanatics Discussion list" <seqfan at list.seqfan.eu>
Subject: [seqfan] n and n^2 use digits 0,1,4,6 only: A136859 - a question

> A136859 contains the numbers n such that n and n^2 use only the digits
> 0,1,4,6.
>
> It appears that n must be 0, 10^k, or 4*10^k. Does anyone know if this is 
> a
> theorem?
>
> I don't know how far it has been checked.
>
> The entry had a formula which was based on there being no other type of
> term, but this was only a conjecture.  I deleted the program and the 
> b-file
> that were based on the conjecture.
>
> Thanks to Maximilian for raising suspicions about the formula.
>
> It would be nice if someone could check that the terms shown are complete,
> that there are no missing numbers. The terms shown are the original ones
> found by Jonathan Wellons, so they are probably correct, but it would be
> good to have a check.
>
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