HP Surestore Disk Array 12h and FC60 - Manual (Page 212)

212 Verifying Disk Array Connection
A quick way to determine the LUN number is to multiply the value of the next-to-last
segment times 8, and add the result to the last segment value. Using the above example, the
LUN number is computed as follows:
(3 x 8) + (5) = 29