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A046418 Repunit of length a(n) has exactly 7 prime factors (counted with multiplicity). 2
12, 20, 21, 22, 27, 35, 61, 65, 74, 82, 85, 141, 146, 177, 187, 194, 226, 299, 323, 329, 337 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Repunit
MATHEMATICA
Select[Range[300], PrimeOmega[FromDigits[PadRight[{}, #, 1]]]==7&] (* Harvey P. Dale, Feb 04 2019 *)
CROSSREFS
Sequence in context: A175765 A138166 A208273 * A171795 A170806 A038528
KEYWORD
nonn,base,more
AUTHOR
Patrick De Geest, Jul 15 1998
EXTENSIONS
More terms from Robert Gerbicz, Nov 22 2010
Changed offset to 1, a(18) added by Ray Chandler, Apr 23 2017
a(19)-a(21) from Max Alekseyev, May 14 2022
STATUS
approved

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Last modified February 26 12:54 EST 2024. Contains 370352 sequences. (Running on oeis4.)