PROVIDENCE — A federal judge sentenced a Providence armed drug dealer to nearly six years in prison, prosecutors said on Friday. Juan Addison pleaded guilty to possession of cocaine with the intent to distribute and to being a felon in possession of a firearm in August, prosecutors said. Addison, 27, was also ordered to serve three years of supervised release once he comes out of prison. He was arrested in February after arriving at his home as Providence police detectives were preparing to search it. He was carrying nearly 3.5 grams of cocaine and more than $1,800 in cash.