2^phi(n) - phi(n).

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =12a(5) =2a(6) =58a(7) =12a(8) =58a(9) =12a(10) =1014a(11) =12a(12) =4084a(13) =58a(14) =248a(15) =248a(16) =65520a(17) =58a(18) =262126a(19) =248a(20) =4084a(21) =1014a(22) =4194282a(23) =248a(24) =1048556a(25) =4084a(26) =262126a(27) =4084a(28) =268435428a(29) =248