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A119761
Values n such that the largest prime factor of repunit R_n=(10^n -1)/9 is a unique prime,i.e.,whose reciprocal has unique decimal period length.
0
2, 3, 4, 6, 9, 10, 12, 14, 18, 19, 23, 24, 36, 38, 39, 46, 48, 62, 78, 93, 96, 106, 120, 134, 150, 186, 196, 240, 268, 294, 300, 317, 320
OFFSET
1,1
EXAMPLE
18 is in the sequence because R_18=3^2*7*11*13*19*37*52579*333667 and 333667 is the only prime with period 9: 1/333667 =0.000002997000002997...
CROSSREFS
KEYWORD
more,nonn,base
AUTHOR
Lekraj Beedassy, Jun 18 2006
EXTENSIONS
Corrected and extended by Hans Havermann, Jun 22 2006
a(25)-a(33) from Ray Chandler, May 09 2017
STATUS
approved