a(n) = phi(C(n)) / gcd(C(n)-1, phi(C(n))), where C(n) is the n-th Cullen number.

Terms

a(0) =1a(1) =1a(2) =3a(3) =5a(4) =3a(5) =33a(6) =5a(7) =33a(8) =341a(9) =1045a(10) =189a(11) =1299a(12) =891a(13) =4437a(14) =9477a(15) =581a(16) =3855a(17) =105525a(18) =27825a(19) =23751a(20) =173043a(21) =10531345a(22) =56511a(23) =2386125a(24) =380955a(25) =256861a(26) =24926139a(27) =5108467a(28) =32397379a(29) =930343095