a(n) = (2*n + 1)*(12 + 11*n + 93*n^2 + 4*n^3)/3.

Terms

a(0) =4a(1) =120a(2) =730a(3) =2310a(4) =5400a(5) =10604a(6) =18590a(7) =30090a(8) =45900a(9) =66880a(10) =93954a(11) =128110a(12) =170400a(13) =221940a(14) =283910a(15) =357554a(16) =444180a(17) =545160a(18) =661930a(19) =795990a(20) =948904a(21) =1122300a(22) =1317870a(23) =1537370a(24) =1782620a(25) =2055504a(26) =2357970a(27) =2692030a(28) =3059760a(29) =3463300