A075775 Numbers k that divide phi(Fibonacci(k)).

1, 10, 11, 12, 14, 15, 18, 20, 21, 22, 24, 25, 26, 27, 28, 29, 30, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 46, 48, 49, 50, 51, 52, 53, 54, 55, 56, 58, 60, 62, 63, 64, 65, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 88, 89, 90, 91, 92, 93

Offset: 1

Author

Benoit Cloitre, Oct 09 2002

Keywords

• easy
• nonn

Comments

This sequence is infinite (Luca, 2002). - Amiram Eldar, Jan 12 2022

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1343
• Florian Luca, Problem H-590, Advanced Problems and Solutions, The Fibonacci Quarterly, Vol. 40, No. 5 (2002), p. 472; Arithmetic Functions of Fibonacci Numbers, Solution to Problem H-590 by J.-Ch. Schlage-Puchta and J. Spilker, ibid., Vol. 41, No. 4 (2002), pp. 382-384.

Crossrefs

Cf. A000010, A000045, A065449.

Programs

Mathematica

Select[Range[100],Divisible[EulerPhi[Fibonacci[#]],#]&] (* Harvey P. Dale, Jun 11 2015 *)