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A145712
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Number of primes p in the range 9 < p <= prime(10^n) that have most significant and least significant decimal digit both equal to 9.
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3
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OFFSET
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1,3
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LINKS
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EXAMPLE
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a(3)=2 because out of the first 1000 primes, only two have first and last digits 9, 919 and 929.
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CROSSREFS
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KEYWORD
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hard,nonn,base
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AUTHOR
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EXTENSIONS
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Better definition from R. J. Mathar, Aug 04 2010
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STATUS
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approved
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