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A108654
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Numbers k such that 10^k - 117 is prime.
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0
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3, 4, 6, 7, 9, 15, 27, 40, 72, 134, 170, 204, 237, 240, 285, 288, 592, 613, 1443, 1524, 2289, 2292, 16326, 19492
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OFFSET
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1,1
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LINKS
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EXAMPLE
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If k=3 then 10^k - 117 = 883 (prime).
If k=40 then 10^k - 117 = 9999999999999999999999999999999999999883 (prime).
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MAPLE
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a := proc (n) if isprime(10^n-117) = true then n else end if end proc; seq(a(n), n = 1 .. 1500); # Emeric Deutsch, Jul 09 2007
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MATHEMATICA
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Select[Range[3, 2500], PrimeQ[10^#-117]&] (* Harvey P. Dale, Feb 18 2011 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,hard,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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