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A181139
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Numbers n such that R(n)^3 + R(n)^2 + 1 is prime, where R(n)=(10^n-1)/9.
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0
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..8.
J. Earls, Computations and Solutions for y^3 = x^2 + k, Scribd.
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MATHEMATICA
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okQ[n_]:=Module[{x=FromDigits[PadRight[{}, n, 1]]}, PrimeQ[x^3+x^2+1]]; Select[Range[5000], okQ] (* From Harvey P. Dale, Nov 04 2011 *)
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CROSSREFS
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Sequence in context: A095412 A074428 A125052 * A162093 A052828 A214915
Adjacent sequences: A181136 A181137 A181138 * A181140 A181141 A181142
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KEYWORD
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more,nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Oct 06 2010
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STATUS
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approved
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