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A064083 Zsigmondy numbers for a = 7, b = 1: Zs(n, 7, 1) is the greatest divisor of 7^n - 1^n (A024075) that is relatively prime to 7^m - 1^m for all positive integers m < n. 10
6, 1, 19, 25, 2801, 43, 137257, 1201, 39331, 2101, 329554457, 2353, 16148168401, 102943, 4956001, 2882401, 38771752331201, 117307, 1899815864228857, 1129901, 11898664849, 247165843, 4561457890013486057, 5762401, 79797014141614001 (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. III. (1892) 265-284.
CROSSREFS
Sequence in context: A157386 A157396 A019430 * A152249 A167580 A080213
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 28 14:21 EDT 2024. Contains 371254 sequences. (Running on oeis4.)