Largest solution of phi(x) = 2^n.

Terms

a(0) =2a(1) =6a(2) =12a(3) =30a(4) =60a(5) =120a(6) =240a(7) =510a(8) =1020a(9) =2040a(10) =4080a(11) =8160a(12) =16320a(13) =32640a(14) =65280a(15) =131070a(16) =262140a(17) =524280a(18) =1048560a(19) =2097120a(20) =4194240a(21) =8388480a(22) =16776960a(23) =33553920a(24) =67107840a(25) =134215680a(26) =268431360a(27) =536862720a(28) =1073725440a(29) =2147450880