Let (an)n=1∞ be a real sequence such that an=(n−1)a1+(n−2)a2+⋯+2an−2+an−1 for every n≥3. If a2011=2011 and a2012=2012, what is a2013?<spanclass=′latex−bold′>(A)</span>6025<spanclass=′latex−bold′>(B)</span>5555<spanclass=′latex−bold′>(C)</span>4025<spanclass=′latex−bold′>(D)</span>3456<spanclass=′latex−bold′>(E)</span>2013