[seqfan] Re: Eventually-signed sequences

Rick Shepherd rlshepherd2 at gmail.com
Sat Mar 27 05:03:50 CET 2010


It's useful to be able to do -keyword:nonn because the default search on,
say,

1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16

returns lots of sequences such as A022993, where the matches (in this order)
are
only on negative terms.

If you know you're looking only for strictly increasing sequences....

Rick
On Fri, Mar 26, 2010 at 11:20 PM, Charles Greathouse <
charles.greathouse at case.edu> wrote:

> I think that if sign and nonn refer only to the initial terms in the
> STU/VWX lines then there's really no value.  But if they refer to the
> entire sequence, there's surely some value, just like ,mult,.
>
> Does anyone use these in their searches?  I will on occasion, but
> rarely compared to other keywords like base.
>
> Charles Greathouse
> Analyst/Programmer
> Case Western Reserve University
>
>  On Fri, Mar 26, 2010 at 5:42 PM, Alonso Del Arte
> <alonso.delarte at gmail.com> wrote:
> > So you're saying that nonn and sign no longer serve any purpose, either
> for
> > humans looking at the OEIS or for the computers handling the OEIS
> (whether
> > server-side or client-side)?
> >
> > I think that if nothing else, those two keywords have value as a
> tradition.
> >
> > Al
> >
> > On Thu, Mar 25, 2010 at 8:37 PM, <franktaw at netscape.net> wrote:
> >
> >> Well, I didn't say that that was what I thought the policy should be,
> >> just that that is what it is. I didn't make the policy; Neil did.
> >>
> >> My personal opinion is that these keywords should be removed. The
> >> program to process submissions can just as easily examine the sequence
> >> to see whether there are any negative terms -- to decide whether to add
> >> %V, %W, and %X lines -- and I don't see any other real use for them.
> >>
> >> Franklin T. Adams-Watters
> >>
> >> -----Original Message-----
> >> From: Alonso Del Arte <alonso.delarte at gmail.com>
> >>
> >> The policy as described by Franklin certainly makes it easy to handle
> >> sequences for which we are not certain that they do or do not contain
> >> negative numbers. Still, I think it would be better for the sign
> >> keyword to
> >> apply even if no negative terms are "visible," and for sequences of
> >> unknown
> >> status to go off the best thinking on the subject (e.g., in the case of
> >> A086811, since H. Moller who wrote the paper cited for that sequence
> >> thinks
> >> it contains no negative terms, it should be nonn rather than sign).
> >>
> >> Just my two cents,
> >> Al
> >>
> >> On Thu, Mar 25, 2010 at 7:28 PM, <franktaw at netscape.net> wrote:
> >>
> >> > The policy has long been that the sequence should have the "sign"
> >> > keyword if there are negative values entered in the sequence -- that
> >> > is, in the %V, %W, and %X lines.  So your 85 examples below should be
> >> > "nonn".  It looks like your 20 "nonn" sequences with negative values
> >> > have them only in b-files or other extension, so they are correct.
> >>
> >>
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