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

1,1

Links

Table of n, a(n) for n=1..27.

P. De Geest, Repunits prime factors

Makoto Kamada, Factorizations of 11...11 (Repunit)

Eric Weisstein's World of Mathematics, Repunit

Mathematica

Select[Range[320], PrimeOmega[FromDigits[Table[1, #]]]==8&] (* Harvey P. Dale, Sep 04 2018 *)

Crossrefs

Cf. A000042, A001222, A002275, A004022, A004023, A046053.

Sequence in context: A116565 A305060 A039615 * A063770 A161923 A309145

Adjacent sequences: A046416 A046417 A046418 * A046420 A046421 A046422

Keyword

nonn,base,more

Author

Patrick De Geest, Jul 15 1998

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

Status

approved