A046419 Repunit of length a(n) has exactly 8 prime factors (counted with multiplicity).
28, 51, 55, 58, 77, 86, 95, 98, 107, 115, 119, 124, 155, 161, 193, 209, 217, 218, 221, 233, 253, 265, 295, 298, 303, 314, 346
Offset: 1
Links
- P. De Geest, Repunits prime factors
- Makoto Kamada, Factorizations of 11...11 (Repunit)
- Eric Weisstein's World of Mathematics, Repunit
Programs
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Mathematica
Select[Range[320],PrimeOmega[FromDigits[Table[1,#]]]==8&] (* Harvey P. Dale, Sep 04 2018 *)
Extensions
More terms from Robert Gerbicz, Nov 22 2010
Offset changed to 1, a(23)-a(26) added by Ray Chandler, Apr 23 2017
a(27) from Max Alekseyev, May 14 2022