A278350 Cototient of Fibonacci(n).

0, 0, 1, 1, 1, 4, 1, 9, 18, 15, 1, 96, 1, 41, 370, 435, 1, 1432, 149, 3565, 5906, 287, 1, 33696, 15025, 753, 106562, 129651, 1, 544040, 2973, 960597, 1782178, 5167, 2413385, 10534320, 501497, 1397033, 31758946, 60862155, 62157, 149373496, 1

Offset: 1

Author

Altug Alkan, Nov 19 2016

Keywords

• nonn

Comments

a(n) = 1 if Fibonacci(n) is prime.

Crossrefs

Cf. A000045, A051953, A065449.

Programs

Mathematica

Table[Fibonacci[n] - EulerPhi[Fibonacci[n]], {n, 40}] (* Alonso del Arte, Nov 21 2016 *)

PARI

a(n) = fibonacci(n) - eulerphi(fibonacci(n));

Formula

a(n) = A051953(A000045(n)).

a(n) = A000045(n) - A065449(n) for n > 0.