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A108156
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Numbers n such that a(n) is prime, where a(n) = a(n-1) + a(n-2), a(0) = 3794765361567513, a(1) = 20615674205555510.
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0
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138, 163, 190, 523, 1855, 3228, 3579, 6468, 7170, 10230, 12783, 17259, 60139, 91315, 97923, 101823, 156075
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OFFSET
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1,1
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COMMENTS
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In his biography of Paul Erdos, Hoffman cited Wilf's Fibonacci-like primefree sequence (A083216). But, as Weisstein points out, Hoffman inadvertently switched the two initial terms, resulting in a sequence that appears primefree for the first 137 terms. Term 138 is 439351292910452432574786963588089477522344721, which is prime. The first Mathematica program below comes from Weisstein's Mathematica notebook.
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REFERENCES
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Paul Hoffman. The Man Who Loved Only Numbers: The Story of Paul Erdos and the Search for Mathematical Truth. New York: Hyperion, 1998.
Herbert S. Wilf. Letters to the Editor. Math. Mag. 63, 284, 1990.
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LINKS
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Table of n, a(n) for n=1..17.
Eric Weisstein's World of Mathematics, Primefree Sequence.
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MATHEMATICA
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a[1] := 3794765361567513; a[2] := 20615674205555510; a[n_] := a[n] = a[n - 2] + a[n - 1]; Flatten[Position[Table[a[n], {n, 10^4}], _?PrimeQ]] (* Weisstein *)
Flatten[Position[LinearRecurrence[{1, 1}, {3794765361567513, 20615674205555510}, 160000], _?PrimeQ]] (* From Harvey P. Dale, Nov 29 2011 *)
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CROSSREFS
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Cf. A083216.
Sequence in context: A107939 A008888 A045045 * A202441 A187206 A168531
Adjacent sequences: A108153 A108154 A108155 * A108157 A108158 A108159
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KEYWORD
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nonn
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AUTHOR
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Alonso del Arte, Jun 06 2005
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EXTENSIONS
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a(10), a(11) and a(12) from Robert G. Wilson v, Jun 07 2005
a(13) from Eric W. Weisstein, Sep 23, 2005
a(14) from Eric W. Weisstein, Oct 6, 2005)
a(15)-a(16) from Eric W. Weisstein, Oct 10, 2005)
a(17) from Eric W. Weisstein, Nov 9, 2005)
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STATUS
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approved
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