a(n) = 16*n^4 + 4.

Terms

a(0) =4a(1) =20a(2) =260a(3) =1300a(4) =4100a(5) =10004a(6) =20740a(7) =38420a(8) =65540a(9) =104980a(10) =160004a(11) =234260a(12) =331780a(13) =456980a(14) =614660a(15) =810004a(16) =1048580a(17) =1336340a(18) =1679620a(19) =2085140a(20) =2560004a(21) =3111700a(22) =3748100a(23) =4477460a(24) =5308420a(25) =6250004a(26) =7311620a(27) =8503060a(28) =9834500a(29) =11316500