Number of iterations of phi(x) at n needed to reach 1.

Terms

a(0) =0a(1) =1a(2) =2a(3) =2a(4) =3a(5) =2a(6) =3a(7) =3a(8) =3a(9) =3a(10) =4a(11) =3a(12) =4a(13) =3a(14) =4a(15) =4a(16) =5a(17) =3a(18) =4a(19) =4a(20) =4a(21) =4a(22) =5a(23) =4a(24) =5a(25) =4a(26) =4a(27) =4a(28) =5a(29) =4