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Search: id:A126246
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| A126246 |
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a(n) = number of Fibonacci numbers, from among (F(1),F(2),F(3),...F(n)), which are coprime to F(n), where F(n) is the n-th Fibonacci number. |
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+0
2
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| 1, 2, 2, 3, 4, 4, 6, 6, 6, 8, 10, 6, 12, 12, 8, 12, 16, 12, 18, 12, 12, 20, 22, 12, 20, 24, 18, 18, 28, 16, 30, 24, 20, 32, 24, 18, 36, 36, 24, 24, 40, 24, 42, 30, 24, 44, 46, 24, 42, 40, 32, 36, 52, 36, 40, 36, 36, 56, 58, 24, 60, 60, 36, 48, 48, 40, 66, 48, 44, 48, 70, 36, 72
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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Equals A054523 * (1, 1, 0, 0, 0,...). - Gary W. Adamson (qntmpkt(AT)yahoo.com), Apr 17 2007
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EXAMPLE
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F(12) = 144. The six Fibonacci numbers which are coprime to 144 and are <= 144 are: F(1)=1,F(2)=1,F(5)=5,F(7)=13,F(10)=55, and F(11) =89. So a(12) = 6.
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MAPLE
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with(combinat): a:=proc(n) local ct, i: ct:=0: for i from 1 to n do if gcd(fibonacci(i), fibonacci(n))=1 then ct:=ct+1 else ct:=ct fi: od: ct: end: seq(a(n), n=1..90); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 24 2007
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CROSSREFS
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Cf. A054523.
Sequence in context: A015742 A015754 A113967 this_sequence A029936 A114093 A077768
Adjacent sequences: A126243 A126244 A126245 this_sequence A126247 A126248 A126249
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Mar 08 2007
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 24 2007
More terms from Gary W. Adamson (qntmpkt(AT)yahoo.com), Apr 17 2007
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