login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A046419 Repunit of length a(n) has exactly 8 prime factors (counted with multiplicity). 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..26.

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 A039772

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 16 21:39 EST 2019. Contains 320200 sequences. (Running on oeis4.)