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A165691
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Primes p such that pi(p) is the product of the first digit of p and the rest of the number.
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0
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OFFSET
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1,1
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COMMENTS
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A subsequence of A112013. There is no further term up to 3*10^10.
a(7) > 2.07*10^12. - Giovanni Resta, Feb 27 2013
a(7) > 10^17. - Chai Wah Wu, Apr 15 2021
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LINKS
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Table of n, a(n) for n=1..6.
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EXAMPLE
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619=prime(6*19), so 619 is in the sequence.
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MATHEMATICA
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Do[If[h=IntegerDigits[Prime[m]]; m==h[[1]]*FromDigits[Delete[h, 1]],
Print[Prime[m]}]], {m, 355000}]
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CROSSREFS
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Cf. A000040, A112013.
Sequence in context: A146658 A145440 A112013 * A154419 A208399 A097223
Adjacent sequences: A165688 A165689 A165690 * A165692 A165693 A165694
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KEYWORD
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hard,more,nonn,base
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AUTHOR
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Farideh Firoozbakht, Oct 14 2009
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EXTENSIONS
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a(6) from Giovanni Resta, Feb 27 2013
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STATUS
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approved
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