[seqfan] Re: multiplicative set-like sequences

Juan Arias de Reyna arias at us.es
Sat Feb 26 10:24:54 CET 2011


I speak as a  user of OEIS:

The concept of multiplicative sequence is found in almost any
elementary book on Number Theory: (a_n) is multiplicative  if
gcd(n,m)=1 implies  a_{nm}=a_n a_m.

I consider that this other concept must be clearly separated 
from that now proposed:

> "mn in the the sequence if m,n are in the sequence and g.c.d.(m,n)=1"

Call it as set multiplicative sequences or something similar and consider
a new keyword.  (I suggest set-mult )

The same word for two different meanings is surely a bad election.

Best regards,
Juan Arias de Reyna




El 26/02/2011, a las 08:46, Max Alekseyev escribió:

> Neil,
> 
> To avoid confusion, we need then to extended the definition of the
> 'mult' keyword given at http://oeis.org/eishelp2.html#RK
> with
> "mn in the the sequence if m,n are in the sequence and g.c.d.(m,n)=1"
> 
> or maybe introduce a new keyword like "mult2" (I'm still not sure if
> it is a good idea to have two distinct definitions for the same
> keyword).
> 
> Regards,
> Max
> 
> On Wed, Feb 16, 2011 at 8:06 PM, N. J. A. Sloane <njas at research.att.com> wrote:
>>> Should such set-like sequences are also marked with the 'mult' keyword?
>> A typical candidate would be A023172.
>> 
>> My answer is Yes, certainly!
>> Neil
>> 
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