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Search: id:A100415
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| A100415 |
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Numbers n such that n is R(n)-th nonprime number, where R(n) is the digit reversal of n (A018252(A004086(n))=n). |
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+0
2
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| 1, 64, 524, 534, 58725, 907538, 6264385, 9438088, 9596598, 27895162, 422984004, 548911025
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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n is in the sequence iff n is not prime and R(n)=n-pi(n). There is no further term up to 3670000000.
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EXAMPLE
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548911025 is in the sequence because 548911025 is the 520118945-th nonprime natural number.
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MATHEMATICA
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Do[s = FromDigits[Reverse[IntegerDigits[n]]]; If[ ! PrimeQ[n] && s == n - PrimePi[n], Print[n]], {n, 548911025}]
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CROSSREFS
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Cf. A018252, A004086, A100412, A100413, A100414.
Sequence in context: A016803 A066430 A115740 this_sequence A070054 A045789 A000525
Adjacent sequences: A100412 A100413 A100414 this_sequence A100416 A100417 A100418
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KEYWORD
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base,more,nonn
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AUTHOR
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Farideh Firoozbakht (mymontain(AT)yahoo.com), Dec 12 2004
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