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A100501
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Numbers n such that 3*10^n+7 is prime.
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3
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1, 2, 5, 8, 24, 29, 84, 110, 129, 176, 593, 1137, 2675, 4992, 26904
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| 593 and 1137 both give primes. - Joao da Silva (zxawyh66(AT)yahoo.com), Sep 30 2005
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LINKS
| Makoto Kamada, Factorizations of 300...007
Sabin Tabirca and Kieran Reynolds, Lacunary Prime Numbers.
Primeform: User group for PFGW & PrimeForm programs
Index entries for primes involving repunits.
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EXAMPLE
| (3*10^5)+7 = (3*100000)+7 = 300000+7 = 300007, which is prime.
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MATHEMATICA
| Do[ If[ PrimeQ[ 3*10^n + 7], Print[ n ]], {n, 0, 20000}]
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CROSSREFS
| Cf. A096774.
Sequence in context: A092097 A195295 A088144 * A142869 A086825 A192476
Adjacent sequences: A100498 A100499 A100500 * A100502 A100503 A100504
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KEYWORD
| more,nonn
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AUTHOR
| Julien Peter Benney (jpbenney(AT)ftml.net), Nov 23 2004
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EXTENSIONS
| a(12) from Mark Hudson (mrmarkhudson(AT)hotmail.com), Nov 26 2004
a(13 & a(14) from Hugo Pfoertner (hugo(AT)pfoertner.org), Nov 29 2004. The next term is > 20000.
a(15) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 12 2010
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