a(n) = n^3*(5*n+3)/2.

Terms

a(0) =0a(1) =4a(2) =52a(3) =243a(4) =736a(5) =1750a(6) =3564a(7) =6517a(8) =11008a(9) =17496a(10) =26500a(11) =38599a(12) =54432a(13) =74698a(14) =100156a(15) =131625a(16) =169984a(17) =216172a(18) =271188a(19) =336091a(20) =412000a(21) =500094a(22) =601612a(23) =717853a(24) =850176a(25) =1000000a(26) =1168804a(27) =1358127a(28) =1569568a(29) =1804786