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A270890
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Numbers k such that (8*10^k + 49)/3 is prime.
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497
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0, 1, 2, 3, 4, 5, 6, 10, 24, 33, 34, 35, 45, 52, 56, 62, 65, 103, 166, 424, 886, 1418, 1825, 4895, 5715, 7011, 7810, 9097, 12773, 14746, 20085, 25359, 27967, 46629, 48507, 68722, 74944, 102541, 118960, 157368
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OFFSET
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1,3
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COMMENTS
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For k>2, numbers such that the digit 2 followed by k-3 occurrences of the digit 6 followed by the digits 83 is prime (see Example section).
a(41) > 3*10^5.
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LINKS
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EXAMPLE
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3 is in this sequence because (8*10^3 + 49)/3 = 2683 is prime.
Initial terms and primes associated:
a(1) = 0, 19;
a(2) = 1, 43;
a(3) = 2, 283;
a(4) = 3, 2683;
a(5) = 4, 26683;
a(6) = 5, 266683, etc.
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MATHEMATICA
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Select[Range[0, 100000], PrimeQ[(8*10^# + 49)/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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