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Max( phi(k) : k=1,2,3,...,n ).
1

%I #7 Jul 23 2023 16:50:40

%S 1,1,2,2,4,4,6,6,6,6,10,10,12,12,12,12,16,16,18,18,18,18,22,22,22,22,

%T 22,22,28,28,30,30,30,30,30,30,36,36,36,36,40,40,42,42,42,42,46,46,46,

%U 46,46,46,52,52,52,52,52,52,58,58,60,60,60,60,60,60,66,66,66,66,70,70

%N Max( phi(k) : k=1,2,3,...,n ).

%F a(1)=1; for n>=2, a(n)=A007917(n)-1.

%t Module[{nn=80,ep},ep=EulerPhi[Range[nn]];Table[Max[Take[ep,n]],{n,nn}]] (* _Harvey P. Dale_, Jul 23 2023 *)

%K easy,nonn

%O 1,3

%A _Benoit Cloitre_, May 11 2002