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A114129
Numbers that factorize into a set of prime factors that are each raised to a different prime exponent.
6
4, 8, 9, 25, 27, 32, 49, 72, 108, 121, 125, 128, 169, 200, 243, 288, 289, 343, 361, 392, 500, 529, 675, 800, 841, 864, 961, 968, 972, 1125, 1152, 1323, 1331, 1352, 1369, 1372, 1568, 1681, 1849, 1944, 2048, 2187, 2197, 2209, 2312, 2809, 2888, 3087, 3125, 3200
OFFSET
1,1
LINKS
MATHEMATICA
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 *)
PROG
(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
(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
CROSSREFS
Subsequence of A130091.
Sequence in context: A093771 A371223 A051676 * A053810 A076702 A051761
KEYWORD
nonn
AUTHOR
Jon Wild, Feb 14 2006
STATUS
approved