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A064081 Zsigmondy numbers for a = 5, b = 1: Zs(n, 5, 1) is the greatest divisor of 5^n - 1^n (A024049) that is relatively prime to 5^m - 1^m for all positive integers m < n. 9
4, 3, 31, 13, 781, 7, 19531, 313, 15751, 521, 12207031, 601, 305175781, 13021, 315121, 195313, 190734863281, 5167, 4768371582031, 375601, 196890121, 8138021, 2980232238769531, 390001, 95397958987501, 203450521 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
By Zsigmondy's theorem, the n-th Zsigmondy number for bases a and b is not 1 except in the three cases (1) a = 2, b = 1, n = 1, (2) a = 2, b = 1, n = 6, (3) n = 2 and a+b is a power of 2.
LINKS
K. Zsigmondy, Zur Theorie der Potenzreste, Monatsh. f. Math. 3 (1892) 265-284.
CROSSREFS
Sequence in context: A072044 A286795 A127138 * A211364 A099438 A002178
KEYWORD
nonn
AUTHOR
Jens Voß, Sep 04 2001
EXTENSIONS
More terms from Vladeta Jovovic, Sep 06 2001
Definition corrected by Jerry Metzger, Nov 04 2009
STATUS
approved

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Last modified March 29 05:28 EDT 2024. Contains 371264 sequences. (Running on oeis4.)