A086833

[Pfoertner, Hugo]

-----Original Message-----
From: franktaw at netscape.net [mailto:franktaw at netscape.net] 
Sent: Thursday, March 23, 2006 01:20
To: seqfan at ext.jussieu.fr
Subject: A086833


The description for A086833 is "Shortest addition chain's minimum member."
Does anyone know what this means?  I can't make any sense out of it, and the
example doesn't really help any.

Franklin T. Adams-Watters
--------------------------------

The sequence is a candidate for the "obsc" keyword. The example "a(23)=5
because 23=1+1+2+1+4+9+5" seems to indicate something like "difference
between final result and previous partial sum", but there are 4 different
addition chains for n=23. See A079300.

The one in the example is 1 2 4 5 9 18 23 with 23-18=5, but another one is 1
2 3 5 10 20 23. Where does a(23)=5 fit here?

BTW, one example of an addition chain for each n<=2048 is given in
http://www.randomwalk.de/sequences/addchains.txt

Hugo Pfoertner