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%I #15 Jan 10 2022 06:33:58
%S 1,2,3,4,5,3,7,8,9,5,11,2,13,7,15,16,17,9,19,5,7,11,23,12,25,13,27,14,
%T 29,15,31,32,33,17,35,3,37,19,13,10,41,7,43,22,45,23,47,8,49,25,51,13,
%U 53,27,11,4,19,29,59,5,61,31,21,64,65,33,67,17,69,35,71
%N Denominator of A047994(n)/n where A047994 is the unitary totient function.
%H Antti Karttunen, <a href="/A319677/b319677.txt">Table of n, a(n) for n = 1..20000</a>
%F a(p) = p, for p prime.
%F a(A002110(n)) = A060753(n).
%F a(n) = n / A323409(n) = n / gcd(n, A047994(n)). - _Antti Karttunen_, Jan 11 2020
%t uphi[n_] := Product[{p, e} = pe; p^e - 1, {pe, FactorInteger[n]}];
%t a[n_] := Denominator[uphi[n]/n];
%t Array[a, 100] (* _Jean-François Alcover_, Jan 10 2022 *)
%o (PARI) a(n)=my(f=factor(n)~); denominator(prod(i=1, #f, f[1, i]^f[2, i]-1)/n);
%Y Cf. A047994, A030163, A305678, A319481, A319676 (numerators), A323409, A331177 (ordinal transform).
%Y Cf. A002110, A060753.
%K nonn,frac
%O 1,2
%A _Michel Marcus_, Sep 26 2018
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