(prime(n)-5)(prime(n)-7)(prime(n)-9)/48.

Terms

a(0) =0a(1) =0a(2) =1a(3) =4a(4) =20a(5) =35a(6) =84a(7) =220a(8) =286a(9) =560a(10) =816a(11) =969a(12) =1330a(13) =2024a(14) =2925a(15) =3276a(16) =4495a(17) =5456a(18) =5984a(19) =7770a(20) =9139a(21) =11480a(22) =15180a(23) =17296a(24) =18424a(25) =20825a(26) =22100a(27) =24804a(28) =35990a(29) =39711