n*nextprime((n-1)!)-nextprime(n!).

Terms

a(0) =0a(1) =1a(2) =2a(3) =-1a(4) =18a(5) =35a(6) =38a(7) =65a(8) =190a(9) =159a(10) =120a(11) =-17a(12) =310a(13) =919a(14) =242a(15) =665a(16) =360a(17) =521a(18) =614a(19) =1751a(20) =578a(21) =651a(22) =616a(23) =2197a(24) =3234a(25) =1007a(26) =1592a(27) =-39a(28) =1720a(29) =6583