[seqfan] Re: Who understands Granville numbers?
Vladimir Shevelev
shevelev at bgu.ac.il
Thu Oct 28 10:12:04 CEST 2010
About A118372. It seems very plausible that every term has the form a(n)=(2^k(n)-1)2^m(n) (maybe, this is known). If so, then there are at least 3 accompanying sequences which are not in OEIS:
for 2^k(n)-1: 3 3 7 3 63 7 3 31 3 7 3 127...
for k(n): 2 2 3 2 6 3 2 5 2 3 2 8...
for m(n): 1 3 2 5 1 5 7 4 9 8 11 6...
Regards,
Vladimir
----- Original Message -----
From: Alonso Del Arte <alonso.delarte at gmail.com>
Date: Thursday, October 28, 2010 1:10
Subject: [seqfan] Who understands Granville numbers?
To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> So I come across the concept of Granville numbers
> (A118372<http://www.research.att.com/~njas/sequences/A118372>)
> in Jean-Marie de Koninck's book *Those Fascinating Numbers*. But
> the concept
> is giving me a headache. Is the definition of the set S
> recursive (one
> having to do a complete divisor tree to figure out membership)
> or am I
> completely misunderstanding it? I've had an easier time doing my
> taxes.
> Al
>
> P.S. Daniel and I have signed up for a couple of slots for
> Sequence of the
> Day in November. Any SeqFan who hasn't yet chosen a Sequence of
> the Day is
> invited to sign up to choose it one day in November or December.
>
> _______________________________________________
>
> Seqfan Mailing list - http://list.seqfan.eu/
>
Shevelev Vladimir
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