A139074 or 0 if no such prime exists.

[drew at math.mit.edu]

To answer the last question first, no, there is no way to add 
placeholders
to the OEIS.

As for including conjectured values vs. including only known terms, 
with the
others in a comment: there are sequences in the OEIS that do it either 
way.
If you look in the index under "conjectured sequences", there are over 
100
sequence that contain conjectured values.

There is one case that must include conjectured values: when the 
sequence
of known initial terms is not long enough.  (This includes as a special 
case
those sequences where no term is known with certainty.)

Franklin T. Adams-Watters

-----Original Message-----
From: drew at math.mit.edu

...

I don't think one should put in "conjectured" zeros.

Drew

drew at math.mit.edu pisze:
> You are right. I interpreted Artur's suggestion as a(n)=0 if no such
> prime exists, but on re-reading I realize this is not quite what he
> said. I totally agree that a(n)=0 if a(n) is unknown is a bad idea.
>
> Is there a way to put in a placeholder (e.g. a ? or *) for unknown
> terms of a sequence so that one can at least enter known values for
> later terms without having to list them all in the comments?
>
> Drew
...




avs> From seqfan-owner at ext.jussieu.fr  Tue Apr 22 17:10:40 2008
avs> From: drew at math.mit.edu
avs> To: franktaw at netscape.net
avs> Cc: seqfan at ext.jussieu.fr
avs> Subject: Re: A139074 or 0 if no such prime exists.
avs> Date: 22 Apr 2008 11:09:30 -0400
avs> 
avs> I apologize for my misinterpretation, which was pointed out to me by David 
avs> Wilson below. For the avoidance of doubt:
avs> 
avs> Good: a(n) = 0 if no such prime exists
avs> Bad: a(n) = 0 if no such prime is known
avs> 
avs> I don't think one should put in "conjectured" zeros.
avs> 
avs> Drew

The architecture of the database allows to put/define in "tokes" like "0" or
"-1" to keep these two things apart, say "0=non-existent" vs "-1=unknown,"
if these two number cannot show up from their core definition.
It's a different question of style whether that ought actually be used: it is
associated with re-flagging the sequences from "nonn" to "sign" and
may mean that people searching for these items may miss them because
no negative numbers are expected.

Richard, www.strw.leidenuniv.nl/~mathar