a(n) = Sum_{j=1..n*(n-1)} (n*j mod (n+j)).

Terms

a(0) =0a(1) =2a(2) =19a(3) =67a(4) =185a(5) =373a(6) =742a(7) =1249a(8) =2053a(9) =3111a(10) =4672a(11) =6467a(12) =9113a(13) =12164a(14) =16124a(15) =20862a(16) =26801a(17) =33376a(18) =41889a(19) =51089a(20) =62342a(21) =75007a(22) =89949a(23) =106152a(24) =125610a(25) =146699a(26) =170757a(27) =197305a(28) =227912a(29) =259643