After a scintillating introductory number at the Smithsonian's Baird Auditorium last night, featured artist LaVaughn Robinson took a mike to introduce what he called his "partners in crime." "Germaine Ingram," he said, pointing to a tuxedoed young woman to one side, "who is a lawyer." "Sandra Janoff," he said, pointing to the other, "who's a schoolteacher." "And me, ladies and gentlemen . . . I'm a neurosurgeon. And right now I'm gettin' ready to operate. Yeah!"

And did he ever -- to the immense delight of the capacity crowd -- as he led the trio into as peppery and intricate a display of jazz-tap exuberance as has been seen hereabouts. The event presented Washington's own Tap Quartet with guest artist David Holmes and the Bill Harris Trio in the first half, and LaVaughn Robinson's Philadelphia Tap Dancers on in the second.

Although Robinson has been dancing for more than 50 years, as one of the younger survivors of the golden age of jazz tap he appears to be still in top physical form. Having toured with Cab Calloway, Charlie Parker, Billie Holiday and other jazz greats in earlier times, he founded his Phildelphia troupe in 1981. The group dances without musical accompaniment -- the tap sound serves as melody, counterpoint and percussion. Robinson and his two superb companions, both of whom studied with him, made a remarkable impression last summer in Washington dancing at the '84 Festival of American Folklife, and this renewed acquaintance confirmed their outstanding artistry.

In a later aside in which he surveyed the master stylists of the past and noted that each had his trademark, Janoff said of Robinson that "patter is his signature, and nobody does it as eloquently as he." "Patter" is a good word for Robinson's specialty: prestissimo tapping, close to the floor, with the breeziness of animated banter. His taps are incredibly distinct and rhythmically even; solid, but never heavy, with a clear, minty ring to the sound. In a sequence of solos at the end of the set, Robinson fairly burnt up the floor. One number made brief allusion to flamenco and ended daringly with a ritard and a quiet pose. Another was his expert impression of Bill (Bojangles) Robinson, charming in its snazzy toe work and leg-crossing hops. Still another was an impression of the legendary Pat Rooney's waltz clog, in both a "straight" and a more swinging version. The pie ce de re'sistance was the last, "For Drummers Only," much longer than the other numbers of the set and a breathtaking exhibition of the pyrotechnics of tap.

Janoff and Ingram are dazzlers in their own right, as they demonstrated both individually and in ensemble. Though not on the same level, the Tap Quartet, led by Artis Brienzo, and the musicians of the Harris Trio got the evening off to an agreeable start.