Chris Brown announced that he’d dumped his girlfriend Karrueche Tran to pursue his “friendship” with Rihanna after the pair hit up Jay-Z’s concert Wednesday and then spent the night together partying at 40/40, Page Six can reveal. Brown and Rihanna were pictured sitting together, with his arm round her, in the VIP area of the Barclays Center in Brooklyn, one row behind Beyoncé. Brown and Rihanna later headed to Jay’s 40/40 club in Flatiron to carry on the party. We’re told they arrived separately but met up again inside a private VIP area. The move comes after the pair were spotted on two consecutive nights canoodling in Manhattan clubs. On Monday, they locked themselves in the bathroom at Griffin, and on Tuesday put on a public show of affection at 1Oak. After their night at 40/40, Brown said yesterday in a statement: “I have decided to be single to focus on my career. I love Karrueche very much, but I don’t want to see her hurt over my friendship with Rihanna. I’d rather be single allowing us to both be happy in our lives.” The R&B star remains on probation for his infamous 2009 attack on Rihanna. Meanwhile, Tran posted a terse tweet Wednesday night — “Bye baby.”