searching for +/-1 sequences
hv at crypt.org
hv at crypt.org
Fri Jan 21 14:46:04 CET 2005
"Eric W. Weisstein" <eww at wolfram.com> wrote:
:Perhaps a dumb question, but how do I search OEIS for sequences containing
:a given sequence of +1 and -1s? If I use superseeker, it matches every
:sequence in which the *absolute value* of the terms is 1. If I try to do
:a word search on OEIS including minus signs (e.g., "-1,-1") I get no hits.
:If I just search for 1,1,1,1,1,..., I get a maximum of 30 hits, so I have
:no guarantee that just because I don't *see* my sequence in the 30
:returned, mine isn't #31.
:
:Concrete example: is the following sequence in OEIS or not (it arises from
:Gauss's generalization of Wilson's theorem)?
:
:-1, -1, -1, -1, -1, -1, 1, -1, -1, -1, 1, -1, -1, 1, 1, -1, -1, -1, 1, 1,
:-1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1,
:-1, 1, 1, -1, -1, 1, -1, -1, 1, 1, -1, -1, 1, 1, 1, -1, -1, 1, -1, -1, 1,
:1, 1, 1, -1, 1, 1, 1, -1, 1, -1, -1, 1, 1, 1, 1, -1, 1, -1, -1, -1, 1, 1,
:-1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1
:
:If it is, how do I actually find that out besides downloading the entire
:database and searching it myself? I checked but didn't see this in the
:FAQ.
Hmm, would superseeker cope if you provide instead the list of indexes
that are '1' (or conversely those that are -1)?
Ie (assuming the first value is a(1)): 7, 11, 14, 15, 19, 20, ...
Hugo
More information about the SeqFan
mailing list