This pianist, singer, and composer didn't have to travel far to find a wealth of inspiration. His native New Orleans was home to the R&B grooves of Professor Longhair (“Red Beans”) and the early-rock energy of Fats Domino (“All By Myself”), but Dr. John also scoured the broader American scene for ideas: The Harlem-style stride-piano bounce of Fats Waller tunes like “Baby Brown” helped shine a light on his path.