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%I #25 May 10 2015 09:46:14
%S 1,1,2,2,4,6,4,6,10,12,8,16,18,22,20,18,28,30,16,36,40,42,46,42,52,58,
%T 60,32,66,70,72,78,54,82,88,96,100,102,106,108,112,110,100,126,64,130,
%U 136,138,148,150,156,162,166,156,172,178,180,190,192,196,198,210
%N Euler's totient function applied to the sequence of prime powers.
%C a(n) = A000010(A000961(n)).
%H Reinhard Zumkeller, <a href="/A085730/b085730.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PrimePower.html">Prime Power</a>.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TotientFunction.html">Totient Function.</a>
%F a(p^e) = (p-1)*p^(e-1).
%F a(n) = (A025473(n)-1)*A025473(n)^(A025474(n)-1).
%o (Haskell)
%o a085730 1 = 1
%o a085730 n = (p - 1) * p ^ (e - 1)
%o where p = a025473 n; e = a025474 n
%o -- _Reinhard Zumkeller_, Feb 16 2012
%o (PARI) list(lim)=my(v=List(primes(primepi(lim)))); listput(v,1); for(e=2, log(lim+.5)\log(2),forprime(p=2,(lim+.5)^(1/e),listput(v, p^e))); apply(n->eulerphi(n),vecsort(Vec(v))) \\ _Charles R Greathouse IV_, Apr 30 2012
%Y Cf. A000010, A000961, A025473, A025474, A207193.
%K nonn
%O 1,3
%A _Reinhard Zumkeller_, Jul 20 2003
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