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

Terms

a(0) =0a(1) =36a(2) =108a(3) =216a(4) =360a(5) =540a(6) =756a(7) =1008a(8) =1296a(9) =1620a(10) =1980a(11) =2376a(12) =2808a(13) =3276a(14) =3780a(15) =4320a(16) =4896a(17) =5508a(18) =6156a(19) =6840a(20) =7560a(21) =8316a(22) =9108a(23) =9936a(24) =10800a(25) =11700a(26) =12636a(27) =13608a(28) =14616a(29) =15660