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A074479
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Largest prime factor of 5^n - 1.
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4
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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; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| S. S. Wagstaff, Jr., The Cunningham Project
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EXAMPLE
| 5^9 - 1 = 1953124 = (2^2)*19*31*829, so a(9) = 829.
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PROG
| (PARI) for(n=1, 32, v=factor(5^n-1); print1(v[matsize(v)[1], 1], ", "))
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CROSSREFS
| 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: A035514 A114009 A143665 * A136150 A155056 A110456
Adjacent sequences: A074476 A074477 A074478 * A074480 A074481 A074482
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KEYWORD
| easy,nonn
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AUTHOR
| Rick L. Shepherd (rshepherd2(AT)hotmail.com), Aug 23 2002
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