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A271428
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Values of k such that F(k)*F(k+1)-1 is a prime, where F(k) is the k-th Fibonacci number (A000045).
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1
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3, 6, 24, 42, 48, 86, 102, 138, 182, 302, 438, 506, 926, 1266, 3600, 23550, 24122, 42410, 51432, 82290
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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6 is in the sequence because F(6)*F(7)-1 = 8*13-1 = 103, which is prime.
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MATHEMATICA
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Select[Range[5 * 10^3], PrimeQ[Fibonacci@ # Fibonacci[# + 1] - 1] &] (* Michael De Vlieger, Apr 07 2016 *)
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PROG
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(PARI) L=List(); for(k=1, 1000, if(ispseudoprime(fibonacci(k)*fibonacci(k+1)-1), listput(L, k))); Vec(L)
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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