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Search: id:A101394
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| A101394 |
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Numbers n such that 4*10^n+9 is prime. |
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+0
2
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OFFSET
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1,2
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COMMENT
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The next term is greater than 9000.
2038 gives a prime.- Joao da Silva (zxawyh66(AT)yahoo.com), Sep 30 2005
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LINKS
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Makoto Kamada, Factorizations of 400...009.
Sabin Tabirca and Kieran Reynolds, Lacunary Prime Numbers.
Index entries for primes involving repunits.
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EXAMPLE
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n = 2, 4, 5, 8, 9 are members since 409, 40009, 400009, 400000009 and 4000000009 are all
prime.
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MATHEMATICA
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Do[ If[ PrimeQ[4*10^n + 9], Print[n]], {n, 0, 10000}]
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CROSSREFS
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Cf. A088275, A056806.
Sequence in context: A065300 A080403 A092739 this_sequence A095031 A100598 A079537
Adjacent sequences: A101391 A101392 A101393 this_sequence A101395 A101396 A101397
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KEYWORD
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hard,nonn
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AUTHOR
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Julien Peter Benney (jpbenney(AT)ftml.net), Jan 15 2005
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