Thanks to the generosity of local teenagers, the Turner Free Library has four tablet computers in circulation in the children’s department. The 20-member Randolph High swim team donated half the earnings from a recent swim-a-thon fund-raiser, which raised $1,670, to the library. Coach Megan Seseske said the top fund-raisers were junior captain Monica Tham, who raised $485, and sophomore Theresa Tran, with $333. Four Nook tablet computers were purchased with the team’s donation. Children will be able to read or play games on the tablets while in the library. To recognize the athletes, a reading alcove, complete with bean bag chairs, was dedicated to the team at a ribbon-cutting ceremony May 19. Among the attendees was state Representative Walter F. Timilty, who presented a citation from the House of Representatives honoring the team. No other public library in the South Shore circulates tablets to children,’’ said children’s librarian Meghan Malone in opening remarks to the appreciative crowd.