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a(n) = phi(n)^(n-phi(n))
1

%I #11 Mar 26 2014 09:30:32

%S 1,1,2,4,4,16,6,256,216,4096,10,65536,12,1679616,2097152,16777216,16,

%T 2176782336,18,68719476736,5159780352,1000000000000,22,

%U 281474976710656,3200000,1283918464548864,198359290368,184884258895036416,28

%N a(n) = phi(n)^(n-phi(n))

%H Vincenzo Librandi, <a href="/A117291/b117291.txt">Table of n, a(n) for n = 1..200</a>

%e a(9) = phi(9)^(9-phi(9)) = 6^3 = 216

%t ep[n_]:=Module[{p=EulerPhi[n]},p^(n-p)]; Array[ep,30] (* _Harvey P. Dale_, Mar 25 2014 *)

%o (PARI) a(n) = eulerphi(n)^(n-eulerphi(n)) \\ _Michel Marcus_, Jun 01 2013

%K nonn

%O 1,3

%A Luc Stevens (lms022(AT)yahoo.com), Apr 23 2006

%E Corrected by _Michel Marcus_, Jun 01 2013