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A274914
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Numbers k such that 88*10^k + 7 is prime.
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0
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1, 2, 3, 4, 8, 14, 17, 19, 24, 26, 30, 43, 81, 85, 171, 267, 282, 2384, 4201, 4450, 6995, 7170, 15049, 15681, 50547, 67691, 109022
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OFFSET
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1,2
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COMMENTS
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For k > 0, numbers k such that the digits 88 followed by k-1 occurrences of the digit 0 followed by the digit 7 is prime (see Example section).
a(28) > 2*10^5.
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LINKS
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EXAMPLE
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4 is in this sequence because 88*10^4 + 7 = 880007is prime.
Initial terms and associated primes:
a(1) = 1, 887;
a(2) = 2, 8807;
a(3) = 3, 88007;
a(4) = 4, 880007;
a(5) = 8, 8800000007, etc.
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MATHEMATICA
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Select[Range[0, 100000], PrimeQ[88*10^# + 7] &]
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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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