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A145713
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Number of primes p in the range 9 < p <= prime(10^n) that begin and end with the same digit.
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4
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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The initial 1 is from the prime 11.
a(4)=1180 because to 10^4 or 10000 primes, ending in 104729=A006988(4), there are 1180 primes with equal and distinct first and last digits: 1 and 1, 3 and 3, 7 and 7 and 9 and 9.
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CROSSREFS
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KEYWORD
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hard,more,nonn,base
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AUTHOR
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EXTENSIONS
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a(6) corrected and a(7)-a(10) added by D. S. McNeil, Aug 29 2010
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STATUS
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approved
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