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a(n) = phi(A090556(n)).
2

%I #22 May 02 2016 07:45:18

%S 1,1,2,2,4,4,4,4,12,12,12,12,24,24,24,24,24,48,96,96,96,192,192,192,

%T 192,192,192,192,192,192,192,384,384,384,384,384,768,768,768,768,768,

%U 768,768,1536,1536,1536,1536,1536,1536,1536,1536,3072,3072,3072,3072,3072

%N a(n) = phi(A090556(n)).

%C Starting at n=9, all known terms are of the form 3*2^k. - _Ivan Neretin_, May 01 2016

%H Ivan Neretin, <a href="/A090557/b090557.txt">Table of n, a(n) for n = 1..308</a>

%t EulerPhi@ NestList[Function[n, SelectFirst[Range[n + 1, 10^4], Divisible[EulerPhi@ #, EulerPhi@ n] &]], 1, 55] (* _Michael De Vlieger_, May 01 2016, Version 10 *)

%Y Cf. A014573, A090556.

%K nonn

%O 1,3

%A _Amarnath Murthy_, Dec 10 2003

%E More terms from _David Wasserman_, Jan 04 2006

%E Missing term a(1) prepended by _Ivan Neretin_, May 01 2016