a(n) = Sum_{d|n} phi(d!).

Terms

a(0) =1a(1) =2a(2) =3a(3) =10a(4) =33a(5) =196a(6) =1153a(7) =9226a(8) =82947a(9) =829474a(10) =8294401a(11) =99533004a(12) =1194393601a(13) =16721511554a(14) =250822656035