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Search: id:A121533
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| A121533 |
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Fibonacci-Lucas prime twins: Prime Fibonacci numbers F[k] such that Lucas numbers L[k] = F[k-1] + F[k+1] are prime too. |
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3
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OFFSET
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1,1
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COMMENT
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Indices for Fibonacci-Lucas prime twins are A080327[n] = {4,5,7,11,13,17,47,...}. Corresponding Lucas-Fibonacci prime twins are A121534[n] = {5,11,29,199,521,3571,6643838879,...}. Probable primes Fibonacci[148091] and Lucas[148091] are the next probable Fibonacci-Lucas and Lucas-Fibonacci prime twins. They have 30949 and 30950 digits.
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EXAMPLE
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a(1) = 3 because Fibonacci[4] = 3 is prime and Lucas[4] = 5 is prime too.
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MATHEMATICA
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Do[f=Fibonacci[n]; l=Fibonacci[n-1]+Fibonacci[n+1]; If[PrimeQ[f]&&PrimeQ[l], Print[{f, l}]], {n, 10000}]
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CROSSREFS
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Cf. A121534, A121535, A000045, A005478, A001605, A001606, A000032, A000204, A005479, A080327.
Sequence in context: A018928 A053630 A155012 this_sequence A087170 A123370 A110407
Adjacent sequences: A121530 A121531 A121532 this_sequence A121534 A121535 A121536
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KEYWORD
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nonn
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Aug 05 2006
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