a(n) = (prime(n)^4 - prime(n)^3)/2.

Terms

a(0) =4a(1) =27a(2) =250a(3) =1029a(4) =6655a(5) =13182a(6) =39304a(7) =61731a(8) =133837a(9) =341446a(10) =446865a(11) =911754a(12) =1378420a(13) =1669647a(14) =2387929a(15) =3870802a(16) =5955991a(17) =6809430a(18) =9925179a(19) =12526885a(20) =14004612a(21) =19228521a(22) =23443267a(23) =31018636a(24) =43808304a(25) =51515050a(26) =55729077