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A101700
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Numbers of the form 3*(10^n-3), where 10^n-3 is prime.
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6
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OFFSET
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1,1
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COMMENTS
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a(5) = 3*(10^140-3) is 141 digits long and is too large to include.
If m is in this sequence then phi(m)=r(m), so this sequence is a subsequence of A069215. a(n)=3*(10^A089675(n)-3), so a(4)=3*(10^17-3), a(5)=3*(10^140-3), a(6)=3*(10^990-3), a(7)=3*(10^1887-3), a(8)=3*(10^3530-3), a(9)=3*(10^5996-3), a(10)=3*(10^13820-3), a(11)=3*(10^21873-3) & a(12)=3*(10 ^26045-3).
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LINKS
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FORMULA
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EXAMPLE
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299999999999999991 is in the sequence because (10^17-3) is prime and 3*(10^17-3)=299999999999999991.
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MATHEMATICA
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Do[If[PrimeQ[10^n-3], Print[3*(10^n-3)]], {n, 150}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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