a(n) = Sum_{composite c <= n} n!/c!.

Terms

a(0) =1a(1) =5a(2) =31a(3) =217a(4) =1737a(5) =15634a(6) =156341a(7) =1719751a(8) =20637013a(9) =268281169a(10) =3755936367a(11) =56339045506a(12) =901424728097