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Denominators of the antiharmonic means B of numbers k such that gcd(k, n) = 1 for numbers n >= 1 and k < n.
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%I #8 Aug 02 2019 22:45:19

%S 1,1,3,2,1,3,3,4,9,1,1,6,3,3,3,8,1,9,3,2,3,1,1,12,5,3,27,6,1,3,3,16,3,

%T 1,3,18,3,3,3,4,1,3,3,2,9,1,1,24,21,5,3,6,1,27,1,12,3,1,1,6,3,3,9,32,

%U 3,3,3,2,3,3,1,36,3,3,15,6,3,3,3,8,81,1,1,6,1,3,3,4,1,9,1,2,3,1,3,48,3,21,9

%N Denominators of the antiharmonic means B of numbers k such that gcd(k, n) = 1 for numbers n >= 1 and k < n.

%C See A175505 - numerators of the antiharmonic means B of numbers k such that gcd(k, n) = 1 for numbers n >= 1 and k < n where B = A053818(n) / A023896(n) = A175505(n) / a(n).

%F a(n) = A175505(n) * A023896(n) / A053818(n).

%t f[n_] := 2Plus @@ (Select[ Range@n, GCD[ #, n] == 1 &]^2)/(n*EulerPhi@n); f[1] = 1; Denominator@ Array[f, 80] (* _Robert G. Wilson v_, Jul 01 2010 *)

%K nonn

%O 1,3

%A _Jaroslav Krizek_, May 31 2010

%E More terms from _Robert G. Wilson v_, Jul 01 2010