Partial sums of the Jordan function J_2(k), for 1 <= k <= n.

Terms

a(0) =0a(1) =1a(2) =4a(3) =12a(4) =24a(5) =48a(6) =72a(7) =120a(8) =168a(9) =240a(10) =312a(11) =432a(12) =528a(13) =696a(14) =840a(15) =1032a(16) =1224a(17) =1512a(18) =1728a(19) =2088a(20) =2376a(21) =2760a(22) =3120a(23) =3648a(24) =4032a(25) =4632a(26) =5136a(27) =5784a(28) =6360a(29) =7200