A154369 Composites k such that gpf(k) mod lpf(k) is prime.

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

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: A343338 A302697 A337987 * A243592 A089966 A327784

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