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A074780 2^n-1 and F(n) are relatively prime, where F(n) denotes the n-th Fibonacci number. 0
1, 2, 3, 5, 6, 7, 9, 13, 14, 15, 17, 19, 21, 23, 25, 26, 27, 29, 31, 34, 35, 37, 38, 39, 41, 42, 43, 45, 46, 47, 49, 51, 53, 57, 59, 61, 62, 63, 65, 67, 69, 71, 73, 74, 75, 79, 81, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 98, 101, 102, 103, 105, 106, 107, 109, 111, 113 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..68.

FORMULA

a(n) seems to be asymptotic to c*n with c=1.7...

MATHEMATICA

Select[Range[120], CoprimeQ[2^#-1, Fibonacci[#]]&] (* Harvey P. Dale, Nov 27 2015 *)

CROSSREFS

Sequence in context: A050747 A261514 A215798 * A292938 A056900 A226808

Adjacent sequences:  A074777 A074778 A074779 * A074781 A074782 A074783

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Sep 07 2002

STATUS

approved

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Last modified August 9 02:14 EDT 2020. Contains 336310 sequences. (Running on oeis4.)