[seqfan] shortest addition-subtraction-multiplication chain

[Max Alekseyev]

SeqFans,
Recent Al Zimmermann's programming contest basically asks for
computing a shortest addition-subtraction-multiplication chain for n!:
http://www.azspcs.net/Contest/Factorials
Is there a sequence in the OEIS that gives the length of such chain
for n (not factorial)? It should be hard to compute it for small n.
Regards,
Max