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A178437
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Numbers n such that 10^n - 81 is prime.
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0
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2, 3, 17, 19, 31, 37, 43, 91, 339, 367, 407, 1135, 1175, 8653, 11987, 15793
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OFFSET
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1,1
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COMMENTS
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The next term, if one exists, is >100000. [From Robert Price, Apr 25 2011]
See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable/proven prime - search on "99919".
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LINKS
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Table of n, a(n) for n=1..16.
Makoto Kamada, List of near-repdigit-related prime numbers.
Index entries for primes involving repunits.
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EXAMPLE
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10^3 - 81 = 919 which is a prime number.
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MATHEMATICA
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nMax=1000; Do[If[PrimeQ[10^n-81], Print[n]], {n, nMax}]
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CROSSREFS
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Cf. A108330, A108328.
Sequence in context: A135931 A215323 A215351 * A215360 A215380 A215376
Adjacent sequences: A178434 A178435 A178436 * A178438 A178439 A178440
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KEYWORD
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more,nonn
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AUTHOR
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Robert Price, Dec 21 2010
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STATUS
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approved
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