a(n) = n^2*(n+1)^2/2.

Terms

a(0) =0a(1) =2a(2) =18a(3) =72a(4) =200a(5) =450a(6) =882a(7) =1568a(8) =2592a(9) =4050a(10) =6050a(11) =8712a(12) =12168a(13) =16562a(14) =22050a(15) =28800a(16) =36992a(17) =46818a(18) =58482a(19) =72200a(20) =88200a(21) =106722a(22) =128018a(23) =152352a(24) =180000a(25) =211250a(26) =246402a(27) =285768a(28) =329672a(29) =378450