Thanks to Star Strider's investigative work, I foundthis page that says that the OLR value is the number of hours since 1-1-1 00:00:00. This suggests to me that your conversion should be
datestr(17298624/24+365)
That's a few days off from the date you specify, but it is close.
Also,this page specifically discusses use of MATLAB to read files from this data source.
Best Answer