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A279795
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Numbers n such that F(n) and F(n-2) are both prime where F(n) = A000045(n).
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4
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OFFSET
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1,1
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COMMENTS
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Terms n of A001605 such that n-2 is also a term of A001605. Surprisingly, the first 4 terms minus 2, { 3, 5, 11, 431 }, are the first four terms of A101315 which also relates to simultaneously prime { m+2, F(m) and F(m)+2 }, but where F is a different function, m -> (m-1)^2 + 1. - M. F. Hasler, Dec 24 2016
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LINKS
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FORMULA
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EXAMPLE
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13 is a term because Fibonacci(13) = 233 and Fibonacci(11) = 89 are both prime.
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MATHEMATICA
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Select[Range[10^4], Times @@ Boole@ Map[PrimeQ@ Fibonacci@ # &, {#, # - 2}] > 0 &] (* Michael De Vlieger, Jan 21 2017 *)
Flatten[Position[Partition[Fibonacci[Range[580]], 3, 1], _?(AllTrue[ {#[[1]], #[[3]]}, PrimeQ]&), 1, Heads->False]]+2 (* Harvey P. Dale, Oct 01 2021 *)
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PROG
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(PARI) isok(n) = isprime(fibonacci(n)) && isprime(fibonacci(n-2)); \\ Michel Marcus, Jan 14 2017
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CROSSREFS
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KEYWORD
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more,nonn
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AUTHOR
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STATUS
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approved
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