Checking correctness of A079300

David Wilson davidwwilson at comcast.net
Sat Apr 1 00:25:17 CEST 2006


Ok, never mind.

My new program only counts Brauer chains (addition chains where every element is 
the sum of the previous element and some element) whereas there are addition 
chains which are not Brauer chains (some element is the sum of two elements 
before the previous element).

The 9 minimal chains I listed in my previous post:

(1 2 4 8 12 13)
(1 2 4 8 9 13)
(1 2 4 6 12 13)
(1 2 4 6 7 13)
(1 2 4 5 9 13)
(1 2 3 6 12 13)
(1 2 3 6 7 13)
(1 2 3 5 10 13)
(1 2 3 5 8 13)

are all Brauer chains.  However, there is an additional minimal chain that is 
non-Brauer:

(1 2 4 5 8 13)

making 10 in all, hence A079300(13) = 10 is correct.  I will modify my program 
and see if it agrees.

Also, my earlier observation that A008297 counts addtion chains for n is wrong, 
it counts Brauer chains. 






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