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A227243
Powerful numbers n such that n/phi(n) >= e^gamma*log log n.
1
4, 8, 9, 16, 36, 72, 108, 144, 216, 900, 1800, 2700, 3600, 44100, 88200
OFFSET
1,1
COMMENTS
The sequence is complete.
FORMULA
A001694 INTERSECT A100966.
MATHEMATICA
PowerfulQ[1] := True; PowerfulQ[n_Integer?Positive] := Min[Last /@ FactorInteger[n]] > 1; Select[Range[100], PowerfulQ[#] && #/EulerPhi[#] >= E^EulerGamma*Log[Log[#]] &] (* G. C. Greubel, Oct 02 2017 *)
PROG
(PARI) a=exp(Euler); for(n=4, 88200, if(ispowerful(n)&&n/eulerphi(n)>=a*log(log(n)), print1(n, ", ")));
CROSSREFS
Sequence in context: A285438 A089042 A340093 * A272575 A020145 A202271
KEYWORD
nonn,easy,fini,full
AUTHOR
STATUS
approved