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!)
A114129 Numbers that factorize into a set of prime factors that are each raised to a different prime exponent. 6

%I #10 Sep 08 2016 11:45:28

%S 4,8,9,25,27,32,49,72,108,121,125,128,169,200,243,288,289,343,361,392,

%T 500,529,675,800,841,864,961,968,972,1125,1152,1323,1331,1352,1369,

%U 1372,1568,1681,1849,1944,2048,2187,2197,2209,2312,2809,2888,3087,3125,3200

%N Numbers that factorize into a set of prime factors that are each raised to a different prime exponent.

%H Harvey P. Dale, <a href="/A114129/b114129.txt">Table of n, a(n) for n = 1..1000</a>

%t dpeQ[n_]:=Module[{exps=Transpose[FactorInteger[n]][[2]]},CompositeQ[n] && Length[ Union[exps]]==Length[exps]&&AllTrue[exps,PrimeQ]]; Select[ Range[ 3500],dpeQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Jul 02 2016 *)

%o (PARI) isok(n) = {nbf = omega(n); f = factor(n); for (i = 1, nbf, if (! isprime(f[i, 2]), return (0)); for (j = i+1, nbf, if (f[i, 2] == f[j, 2], return (0)););); return (1);} \\ _Michel Marcus_, Aug 18 2013

%o (PARI) is(n)=if(n<4, return(0)); my(f=factor(n)[,2]); vecmin(apply(isprime,f)) && #Set(f)==#f \\ _Charles R Greathouse IV_, Sep 08 2016

%Y Subsequence of A130091.

%K nonn

%O 1,1

%A _Jon Wild_, Feb 14 2006

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 April 25 05:49 EDT 2024. Contains 371964 sequences. (Running on oeis4.)