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A115073
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Numbers n such that 10^(2n+1)-7*10^n-1 is prime.
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46
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1, 8, 9, 352, 530, 697, 1315, 1918, 2874, 5876, 6768, 62938, 134739
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OFFSET
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1,2
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REFERENCES
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C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
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LINKS
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FORMULA
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MATHEMATICA
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Do[If[PrimeQ[10^(2n + 1) - 7*10^n - 1], Print[n]], {n, 3000}]
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PROG
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(PARI) for(n=0, 1e4, if(ispseudoprime(t=10^(2*n+1)-7*10^n-1), print1(t", "))) \\ Charles R Greathouse IV, Jul 15 2011
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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