Checking correctness of A079300

[David Wilson]

Many moons ago, I authored A079300, the number of minimal addition chains of n, 
calculated from a long-lost program.  I have just written an new program, which 
disagrees with A079300.  The existing sequence has A079300(13) = 10, while my 
new program finds only 9 minimal addition chains for 13,
namely:

(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)

Can anyone help me unravel the discrepancy?

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- David Wilson