a(n) = 625*n^2 + 2*n.

Terms

a(0) =627a(1) =2504a(2) =5631a(3) =10008a(4) =15635a(5) =22512a(6) =30639a(7) =40016a(8) =50643a(9) =62520a(10) =75647a(11) =90024a(12) =105651a(13) =122528a(14) =140655a(15) =160032a(16) =180659a(17) =202536a(18) =225663a(19) =250040a(20) =275667a(21) =302544a(22) =330671a(23) =360048a(24) =390675a(25) =422552a(26) =455679a(27) =490056a(28) =525683a(29) =562560