Sum of distinct products i*j with 1 <= i, j <= n.

Terms

a(0) =1a(1) =7a(2) =25a(3) =61a(4) =136a(5) =244a(6) =440a(7) =680a(8) =1022a(9) =1472a(10) =2198a(11) =2882a(12) =4065a(13) =5241a(14) =6681a(15) =8265a(16) =10866a(17) =13116a(18) =16726a(19) =19786a(20) =23566a(21) =27922a(22) =34270a(23) =38902a(24) =45502a(25) =52600a(26) =60430a(27) =68326a(28) =80941a(29) =89671