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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A187104 Numbers n with property that the largest proper divisor of n is a cube. 3
16, 54, 81, 128, 250, 375, 432, 625, 686, 1024, 1029, 1458, 1715, 2000, 2187, 2401, 2662, 3456, 3993, 4394, 5488, 6591, 6655, 6750, 8192, 9317, 9826, 10125, 10985, 11664, 13718, 14641, 14739, 15379, 16000, 18522, 20577, 21296, 24167, 24334 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Corresponding cubes are: 8, 27, 27, 64, 125, 125, 216, 125, 343, 512, 343, 729, 343, 1000, 729, 343, 1331, 1728, 1331, 2197, 2744, 2197, 1331, 3375, 4096, 1331, 4913, 3375, 2197, 5832, 6859, 1331, 4913, 2197, 8000.

LINKS

Zak Seidov, Table of n, a(n) for n = 1..2671, a(n) up to 10^9

MATHEMATICA

Select[Range[54000], MoebiusMu[#] == 0 && IntegerQ[Divisors[#][[-2]]^(1/3)] &] (* Alonso del Arte, Mar 04 2011 *)

PROG

(PARI) lista(nn) = {forcomposite(n=1, nn, if (ispower(divisors(n)[numdiv(n)-1], 3), print1(n, ", ")); ); } \\ Michel Marcus, Aug 09 2014

CROSSREFS

Cf. A187101 (largest proper divisor is a square).

Sequence in context: A137515 A164324 A197246 * A137741 A167690 A172190

Adjacent sequences:  A187101 A187102 A187103 * A187105 A187106 A187107

KEYWORD

nonn

AUTHOR

Zak Seidov, Mar 04 2011

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified June 25 12:02 EDT 2017. Contains 288710 sequences.