a(n) = 289*n^2 - 2*n.

Terms

a(0) =287a(1) =1152a(2) =2595a(3) =4616a(4) =7215a(5) =10392a(6) =14147a(7) =18480a(8) =23391a(9) =28880a(10) =34947a(11) =41592a(12) =48815a(13) =56616a(14) =64995a(15) =73952a(16) =83487a(17) =93600a(18) =104291a(19) =115560a(20) =127407a(21) =139832a(22) =152835a(23) =166416a(24) =180575a(25) =195312a(26) =210627a(27) =226520a(28) =242991a(29) =260040