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!)
A087550 a(n) = smallest k such that for each r, 2 <= r <= n, there exists a distinct s, n < s <= k, with the same prime signature as r. 0
3, 7, 9, 13, 13, 19, 27, 49, 49, 49, 49, 49, 49, 49, 81, 81, 81, 81, 81, 81, 81, 81, 81, 169, 169, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 343, 361, 361, 361, 361, 361, 361, 361, 361, 361, 361, 361 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,1
LINKS
FORMULA
For sufficiently large n, a(n) = 7^floor(log(n)/log(3)) because log(prime(2m))/log(prime(m)) is largest for m = 2. - David Wasserman, Jun 03 2005
EXAMPLE
a(7) = 19 and For numbers ( 2,3,4,5,6,7) we have the set of numbers ( 11,13,9,17,10,19) with matching prime signatures.
CROSSREFS
Sequence in context: A353103 A087064 A189561 * A235387 A285144 A356138
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Sep 13 2003
EXTENSIONS
More terms from David Wasserman, Jun 03 2005
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 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)