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A101394
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Numbers n such that 4*10^n+9 is prime.
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1
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0, 2, 4, 5, 8, 9, 28, 191, 196, 2038, 34414, 39266
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| No further terms less than 50000.
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LINKS
| 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
| n = 2, 4, 5, 8, 9 are members since 409, 40009, 400009, 400000009 and 4000000009 are all
prime.
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MATHEMATICA
| Do[ If[ PrimeQ[4*10^n + 9], Print[n]], {n, 0, 10000}]
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CROSSREFS
| Cf. A088275, A056806.
Sequence in context: A195364 A200947 A092739 * A095031 A100598 A191535
Adjacent sequences: A101391 A101392 A101393 * A101395 A101396 A101397
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KEYWORD
| nonn
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AUTHOR
| Julien Peter Benney (jpbenney(AT)ftml.net), Jan 15 2005
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EXTENSIONS
| a(10)=2038 from Joao da Silva (zxawyh66(AT)yahoo.com), Sep 30 2005
a(11)-a(12) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010
Edited by Ray Chandler (rayjchandler(AT)sbcglobal.net), Dec 23 2010
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