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A296029
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Numbers k such that 10^k/8 - 1 is prime.
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1
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4, 7, 8, 11, 16, 22, 28, 29, 79, 91, 170, 293, 392, 1898, 2597, 3641, 4099, 8236, 11393, 17969, 18503, 33322
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OFFSET
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1,1
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COMMENTS
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Equivalently, numbers k such that 125*10^(k-3) - 1 is prime.
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LINKS
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EXAMPLE
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1249, 1249999, and 12499999 are prime, so 4, 7, and 8 are in the sequence.
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MATHEMATICA
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PROG
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(PARI) lista(nn) = for(n=4, nn, if(ispseudoprime(10^n/8 - 1), print1(n, ", "))) \\ Iain Fox, Dec 04 2017
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CROSSREFS
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KEYWORD
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nonn,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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