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A271360
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Numbers k such that 5*10^k + 87 is prime.
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0
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1, 2, 3, 4, 6, 16, 38, 39, 46, 61, 62, 100, 116, 152, 190, 298, 472, 642, 688, 1676, 1971, 2338, 4389, 4520, 4986, 7765, 9428, 10820, 18984, 19797, 35360, 42146, 168807
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OFFSET
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1,2
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COMMENTS
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For k>1, numbers such that the digit 5 followed by k-2 occurrences of the digit 0 followed by the digits 87 is prime (see Example section).
a(34) > 2*10^5.
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LINKS
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EXAMPLE
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3 is in this sequence because 5*10^3 + 87 = 5087 is prime.
Initial terms and primes associated:
a(1) = 1, 137;
a(2) = 2, 587;
a(3) = 3, 5087;
a(4) = 4, 50087;
a(5) = 6, 5000087, etc.
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MATHEMATICA
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Select[Range[0, 100000], PrimeQ[5*10^# + 87] &]
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PROG
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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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