[seqfan] Re: Gen. Functs. A039219
Hagen von Eitzen
hagen at von-eitzen.de
Wed Sep 16 08:36:41 CEST 2009
franktaw at netscape.net schrieb:
> And, unfortunately, there are quite a few g.f.s in the OEIS that are
> off by a factor of x or x^2 or so. I fix these when I see them, but a
> review of all the g.f.s in the database is not a realistic possibility.
>
>
I remember from sequences esp. those that are rather lists than
functions N -> N
then when I was able to add a g.f. the formula often looks more natural
without the
extra factor x (i.e. if the list were given as a(0), a(1), ... instead),
hence I can
understand how it may happen that one forgets these offset factors.
In a perfect world, such offset problems should be detectable mostly
automatically,
provided the g.f.s. can be reliably extracted syntactically and
translated to a syntax
feedable to, say, pari and then compare GF+O(x^10) with the first members
of the sequence ...
However, I'm afraid reliable extraction and unified syntax are somewhat
problematic.
Hagen
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