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A333357
Integers that cannot be expressed as the ratio of 2 Fibonacci numbers.
1
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., 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
KEYWORD
nonn,easy
AUTHOR
M. Farrokhi D. G., Jul 24 2020
STATUS
approved