Kerry-born Robert Houlihan (left), who has held conductorships of orchestras in Romania and Hungary, is one of the most consistently interesting conductors to work with the National Symphony Orchestra. That's not to say he gets a great deal of exposure here. He doesn't. But the annual ration of a concert or two has shown him to have a fresh, almost tradition-free approach to the music he tackles. His programme with the NSO on Friday finds him pairing symphonies by Mozart (the Linz) and Mahler (the First). The concerto in the symphonic sandwich is by Salieri. It's for flute and oboe, and the soloists are two NSO principals, William Dowdall, and Matthew Manning.