A039787 and A049091 are duplicates

David Wilson davidwwilson at comcast.net
Thu Jul 14 15:26:48 CEST 2005

I agree with Mr. Klasen.

It can be shown that A039787 includes only primes (in agreement with the 
comment).  Given this, the definition of A039787 devolves to primes p with 
p-1 squarefree, which is precisely A049091.  The reason they are distinct 
sequences in the OEIS is that A039787 omits 2, which it should include.  The 
two sequences should be merged, I prefer the A049091 definition.

----- Original Message ----- 
From: "Lambert Klasen" <Lambert.Klasen at gmx.net>
To: <seqfan at ext.jussieu.fr>
Sent: Thursday, July 14, 2005 6:09 AM
Subject: A039787 and A049091 are duplicates

> dear seqfans,
> there are A039787: phi(a(n)) is equal to the square-free kernel of 
> (a(n)-1)
> and A049091: Primes p such that p-1 is square-free.
> since 1 is in A007947 (the square-free kernel of n)
> prepend 2 to A039787 and both seqences are identical, aren't they?
> best regards
>        Lambert
> -- 
> 5 GB Mailbox, 50 FreeSMS http://www.gmx.net/de/go/promail
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