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Search: id:A128344
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| A128344 |
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Numbers n such that (7^n - 5^n)/2 is prime. |
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20
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OFFSET
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1,1
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COMMENT
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All terms are primes.
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MATHEMATICA
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k=7; Do[p=Prime[n]; f=(k^p-5^p)/(k-5); If[ PrimeQ[f], Print[p] ], {n, 1, 100}]
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CROSSREFS
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Cf. A062572, A128345, A128346, A128347, A128348, A128349, A128350, A128351, A128352, A128353, A128354. Cf. A004061, A082182, A121877, A059802. Cf. A057171, A082387, A122853, A128335, A128336, A128337, A128338, A128339, A128340, A128341, A128342.
Sequence in context: A110337 A132287 A046201 this_sequence A114366 A088092 A082756
Adjacent sequences: A128341 A128342 A128343 this_sequence A128345 A128346 A128347
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KEYWORD
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hard,more,nonn
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 27 2007
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