A Westbrook man has been sentenced to 15 years in federal prison for a series of robberies last year. Paul Sans was also sentenced Tuesday in U.S. District Court in Portland to three years of probation and was ordered to pay more than $19,000 in restitution. He pleaded guilty in October to four counts of bank robbery and one count of interference with commerce by robbery. Prosecutors say the 30-year-old Sans robbed a Portland convenience store on Jan. 11, 2012, then hit Portland credit unions on Jan. 12 and 19, a Windham credit union on Feb. 7 and a Lewiston bank on Feb. 15. He and his getaway driver were caught fleeing the Lewiston robbery. That driver, Maria Mattson, was sentenced to more than four years in prison in December.