a(n) = p*(p - 1)*(73*p^2 - 45*p + 14)/24, where p = prime(n).

Terms

a(0) =18a(1) =134a(2) =1345a(3) =5733a(4) =38280a(5) =76479a(6) =230588a(7) =363546a(8) =792649a(9) =2033451a(10) =2664915a(11) =5454873a(12) =8260270a(13) =10012464a(14) =14337303a(15) =23275109a(16) =35855716a(17) =41007555a(18) =59825238a(19) =75546485a(20) =84478374a(21) =116064351a(22) =141557994a(23) =187394306a(24) =264812328a(25) =311476425a(26) =336995709a(27) =392705408a(28) =423017991