A333357 Integers that cannot be expressed as the ratio of 2 Fibonacci numbers.

6, 9, 10, 12, 14, 15, 16, 19, 20, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 33, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 77, 78, 79, 80

Offset

1,1

Comments

Any product of m > 1 Fibonacci numbers > 1 belongs to the sequence except for 4, 18, 48, and 72.

Links

M. Farrokhi D. G., Table of n, a(n) for n = 1..10000

M. Farrokhi D. G., Some remarks on the equation F_n=kF_m in Fibonacci numbers, J. Integer Seq. 10 (2007), no. 5, Article 07.5.7, 9 pp.

Prog

(GAP) l := Filtered(Set(List(Cartesian([1..21], [1..21]), x -> Fibonacci(x[1] * x[2])/Fibonacci(x[1]))), x -> x < 10000);;
Filtered([1..10000], x ->  not x in l);

Crossrefs

Cf. A000045.

Complement of A031121.

Sequence in context: A337940 A104523 A091886 * A111774 A325170 A325229

Adjacent sequences: A333354 A333355 A333356 * A333358 A333359 A333360

Keyword

nonn,easy

Author

M. Farrokhi D. G., Jul 24 2020

Status

approved