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

[Neil Sloane]

Bob,
No, the definition is correct.  If you look at any of the hints or format
pages, you will
see that the OEIS has basically two kinds of sequences, those
defined by an expression in terms of n (e.g. a(n) = 2^n) and those that
list numbers with a certain property. The latter class of sequences
are called lists, and have offset 1.

Best regards
Neil

Neil J. A. Sloane, President, OEIS Foundation.
11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
Phone: 732 828 6098; home page: http://NeilSloane.com
Email: njasloane at gmail.com


On Fri, Jan 29, 2016 at 9:41 AM, Bob Selcoe <rselcoe at entouchonline.net>
wrote:

> 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.
>>
>> _______________________________________________
>>
>> Seqfan Mailing list - http://list.seqfan.eu/
>>
>>
> _______________________________________________
>
> Seqfan Mailing list - http://list.seqfan.eu/
>