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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A304369 Numbers n such that Sum_{d|n, d = 1 or not a perfect power} mu(n/d) is greater than 1 in absolute value. 4
216, 432, 648, 1000, 1080, 1296, 1512, 2000, 2160, 2376, 2744, 2808, 3000, 3024, 3240, 3375, 3672, 4104, 4536, 4752, 4968, 5000, 5488, 5616, 6000, 6264, 6480, 6696, 6750, 7000, 7128, 7344, 7560, 7776, 7992, 8208, 8232, 8424, 8856, 9072, 9261, 9288, 9936, 10000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[10000], Abs[Sum[If[d>1&&GCD@@FactorInteger[d][[All, 2]]===1, MoebiusMu[#/d], 0], {d, Divisors[#]}]]>1&]

PROG

(PARI) ok(n)={abs(sumdiv(n, d, if(ispower(d), 0, moebius(n/d)))) > 1} \\ Andrew Howroyd, Aug 26 2018

CROSSREFS

Cf. A000005, A000961, A001221, A001597, A001694, A005117, A007916, A008683, A091050, A304326, A304327, A304362, A304364, A304365.

Sequence in context: A224549 A327284 A043371 * A074266 A208089 A275154

Adjacent sequences:  A304366 A304367 A304368 * A304370 A304371 A304372

KEYWORD

nonn

AUTHOR

Gus Wiseman, May 11 2018

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 16 06:21 EDT 2019. Contains 328048 sequences. (Running on oeis4.)