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A101398
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Numbers n such that 4*10^n-3 is prime.
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1
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1, 2, 14, 20, 30, 44, 66, 260, 872, 8846, 26744, 57506
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| See Kamada link for search limit and prime vs. PRP status.
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LINKS
| Makoto Kamada, Factorizations of 399...997.
Index entries for primes involving repunits.
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EXAMPLE
| n = 1, 2, 14, 20 are members since 37, 397, 399999999999997 and 399999999999999999997
are prime numbers.
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MATHEMATICA
| Do[ If[ PrimeQ[4*10^n - 3], Print[n]], {n, 0, 10000}]
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CROSSREFS
| Cf. A089675.
Sequence in context: A032476 A059205 A187261 * A131221 A138047 A005237
Adjacent sequences: A101395 A101396 A101397 * A101399 A101400 A101401
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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(11)-a(12) from Kamada data by Robert Price (pamandbobprice(AT)yahoo.com), Dec 13 2010
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