[seqfan] Re: A004249, A007516
Maximilian Hasler
maximilian.hasler at gmail.com
Wed Jun 10 23:12:54 CEST 2009
On Wed, Jun 10, 2009 at 3:00 PM, <franktaw at netscape.net> wrote:
> I would say that A007516 is clearly erroneous. Compare A014221.
the sequence
A007516 (2^2^...^2) (n times) + 1.
was obviously added knowing about the xref'd sequence
A004249 (2^2^...^2) (with n 2's) + 1.
2,3,5,17,...
and thus "wants" to be different from this,
i.e. in A007516 the intention is NOT to think of an empty ^ tower,
but of nothing written before the +1:
For n=0, write no "2" (and consequently no "^") at all.
Then you should see :
+1
which means, a(0) = 1.
I must admit that for A004249 one could get the same interpretation
(maybe even "more" than for the current %N A007516).
Maybe one could add there
%C A004249 For n=0, the empty product is meant.
(or something similar).
The intended definition of A007516 (i.e. the sequence: +1, 2+1, 2^2+1, ...)
could be made more precise by
%N A007516 a(n) = 2^2^...^2 + 1, with n "2"s, and "^" written in-between them.
%C A007516 Here, n=0 corresponds to "nothing in front of +1". See
A004249 for another interpretation, using the empty product instead.
Maximilian
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