a(n) = Sum_{d|n} phi(d)*Bell(n/d) for n>0, a(0) = 0.

Terms

a(0) =0a(1) =1a(2) =3a(3) =7a(4) =19a(5) =56a(6) =214a(7) =883a(8) =4163a(9) =21163a(10) =116039a(11) =678580a(12) =4213848a(13) =27644449a(14) =190900217a(15) =1382958677a(16) =10480146333a(17) =82864869820a(18) =682076827740