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A270339
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Numbers k such that (11*10^k + 19)/3 is prime.
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502
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1, 2, 3, 9, 17, 18, 20, 24, 29, 36, 48, 114, 126, 135, 153, 170, 241, 363, 483, 579, 681, 948, 2483, 2798, 3081, 5137, 5640, 6890, 7080, 12600, 16929, 24253, 24793, 35546, 52956, 69645, 133831
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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 3 followed by k-2 occurrences of the digit 6 followed by the digits 73 is prime (see Example section).
a(38) > 2*10^5.
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LINKS
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EXAMPLE
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3 is in this sequence because (11*10^3 + 19)/3 = 3673 is prime.
Initial terms and primes associated:
a(1) = 1, 43;
a(2) = 2, 373;
a(3) = 3, 3673;
a(4) = 9, 3666666673;
a(5) = 17, 366666666666666673, etc.
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MATHEMATICA
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Select[Range[0, 100000], PrimeQ[(11*10^# + 19)/3] &]
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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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