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%I #17 Aug 05 2019 07:37:16
%S 1,2,8,12,32,48,108,128,192,432,512,768,972,1728,2048,3072,3888,6912,
%T 8192,8748,12288,15552,27648,32768,34992,49152,62208,78732,110592,
%U 131072,139968,196608,248832,314928,442368,524288,559872,708588,786432,995328,1259712
%N Numbers n such that n=phi(n)*core(n) where phi(x) is the Euler totient function and core(x) the squarefree part of x (the smallest integer such that x*core(x) is a square).
%H Amiram Eldar, <a href="/A069185/b069185.txt">Table of n, a(n) for n = 1..10000</a>
%F {1} union {numbers of form 2^(2u+1)} union {numbers of form 4^(u+1)*3^(2v+1)} u, v>=0. - _Benoit Cloitre_, Aug 31 2004
%t f[p_, e_] := (p^e - p^(e - 1)) * p^Mod[e, 2]; aQ[1] = True; aQ[n_] := Times @@ (f @@@ FactorInteger[n]) == n; Select[Range[10000], aQ] (* _Amiram Eldar_, Aug 05 2019 *)
%Y Cf. A000010, A007913.
%K easy,nonn
%O 1,2
%A _Benoit Cloitre_, Apr 14 2002
%E More terms from _Amiram Eldar_, Aug 05 2019
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