[seqfan] Re: Error in the example for A003313

Max Alekseyev maxale at gmail.com
Wed Jul 17 00:58:35 CEST 2013


On Tue, Jul 16, 2013 at 6:25 PM, Rob Arthan <rda at lemma-one.com> wrote:
> The example in A003313 "Length of shortest addition chain for n" is incorrect (or, at best, very misleading). It gives an ASCII-art picture of a tree with positive integer node labels and says that a(n) is the depth of the node with label n in the tree.  This is taken from Knuth, but the statement is claiming much more than Knuth does.

What exactly does Knuth state about this tree?

> In fact, it is not possible to extend this tree to include.all values of n.

Then it would make sense to add the sequence (if it is not yet in
OEIS) of those n that appear in this tree as well as the sequence of
those n that are missing in the tree.

Regards,
Max



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