a(n) = n^2*(n+1)*(n+2)^2/6.

Terms

a(0) =0a(1) =3a(2) =32a(3) =150a(4) =480a(5) =1225a(6) =2688a(7) =5292a(8) =9600a(9) =16335a(10) =26400a(11) =40898a(12) =61152a(13) =88725a(14) =125440a(15) =173400a(16) =235008a(17) =312987a(18) =410400a(19) =530670a(20) =677600a(21) =855393a(22) =1068672a(23) =1322500a(24) =1622400a(25) =1974375a(26) =2384928a(27) =2861082