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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A154369 Composites k such that gpf(k) mod lpf(k) is prime. 0
15, 33, 35, 45, 51, 65, 69, 75, 85, 87, 99, 115, 119, 123, 133, 135, 141, 143, 153, 159, 161, 165, 175, 177, 185, 207, 213, 215, 217, 225, 231, 235, 245, 249, 255, 259, 261, 265, 267, 297, 303, 319, 321, 323, 325, 329, 335, 339, 345, 357, 363, 365, 369, 375 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..54.

EXAMPLE

Composite(35) = 51 = 17*3 and 17 mod 3 = 2 (prime), so 51 is a term.

Composite(46) = 65 = 13*5 and 13 mod 5 = 3 (prime), so 65 is a term.

Composite(53) = 75 = 5*5*3 and 5 mod 3 = 2 (prime), so 75 is a term.

MAPLE

A020639 := proc(n) numtheory[factorset](n) ; min(op(%)) ; end proc:

A006530 := proc(n) numtheory[factorset](n) ; max(op(%)) ; end proc:

for n from 1 to 500 do if isprime( A006530(A002808(n)) mod A020639(A002808(n)) ) then printf("%d, ", A002808(n) ) ; end if; end do: # R. J. Mathar, May 05 2010

CROSSREFS

Cf. A000040, A002808, A020639, A006530.

Sequence in context: A180815 A177204 A302697 * A243592 A089966 A050384

Adjacent sequences:  A154366 A154367 A154368 * A154370 A154371 A154372

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jan 08 2009

EXTENSIONS

Corrected (133 inserted) and extended by R. J. Mathar, May 05 2010

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 October 15 09:22 EDT 2019. Contains 328026 sequences. (Running on oeis4.)