login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A089341 Numbers n with spf(n) < gpf(n) < 2*spf(n), where spf=A020639, gpf=A006530. 2
6, 12, 15, 18, 24, 35, 36, 45, 48, 54, 72, 75, 77, 91, 96, 108, 135, 143, 144, 162, 175, 187, 192, 209, 216, 221, 225, 245, 247, 288, 299, 323, 324, 375, 384, 391, 405, 432, 437, 486, 493, 527, 539, 551, 576, 589, 637, 648, 667, 675, 703, 713, 768, 847, 851 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
A046665(a(n)) < A020639(a(n));
A081306 without prime powers.
LINKS
Eric Weisstein's World of Mathematics, Smooth Number
PROG
(Haskell)
a089341 n = a089341_list !! (n-1)
a089341_list = filter (\x -> a006530 x < 2 * a020639 x) a024619_list
-- Reinhard Zumkeller, Sep 29 2014
CROSSREFS
Cf. A005279, A006530, A020639, A046665, subsequence of A024619.
Sequence in context: A066312 A309944 A212308 * A256617 A252044 A315617
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jan 03 2004
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)