A278350 - OEIS

%I #11 Nov 21 2016 15:11:31

%S 0,0,1,1,1,4,1,9,18,15,1,96,1,41,370,435,1,1432,149,3565,5906,287,1,

%T 33696,15025,753,106562,129651,1,544040,2973,960597,1782178,5167,

%U 2413385,10534320,501497,1397033,31758946,60862155,62157,149373496,1

%N Cototient of Fibonacci(n).

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

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

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

%t Table[Fibonacci[n] - EulerPhi[Fibonacci[n]], {n, 40}] (* _Alonso del Arte_, Nov 21 2016 *)

%o (PARI) a(n) = fibonacci(n) - eulerphi(fibonacci(n));

%Y Cf. A000045, A051953, A065449.

%K nonn

%O 1,6

%A _Altug Alkan_, Nov 19 2016