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Search: id:A074479
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| A074479 |
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Largest prime factor of 5^n - 1. |
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+0
5
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| 2, 3, 31, 13, 71, 31, 19531, 313, 829, 521, 12207031, 601, 305175781, 19531, 1741, 11489, 466344409, 5167, 3981071, 9161, 519499, 12207031, 332207361361, 390001, 9384251, 305175781, 31051, 234750601, 22125996444329, 7621
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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S. S. Wagstaff, Jr., The Cunningham Project
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EXAMPLE
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5^9 - 1 = 1953124 = (2^2)*19*31*829, so a(9) = 829.
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PROGRAM
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(PARI) for(n=1, 32, v=factor(5^n-1); print1(v[matsize(v)[1], 1], ", "))
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CROSSREFS
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Cf. A074478 (largest prime factor of 5^n + 1), A074477 (largest prime factor of 3^n - 1), A074249 (largest prime factor of 7^n - 1).
Sequence in context: A093712 A035514 A114009 this_sequence A136150 A110456 A128348
Adjacent sequences: A074476 A074477 A074478 this_sequence A074480 A074481 A074482
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KEYWORD
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easy,nonn
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AUTHOR
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Rick L. Shepherd (rshepherd2(AT)hotmail.com), Aug 23 2002
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