This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A175506 #8 Aug 02 2019 22:45:19 %S A175506 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 A175506 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 A175506 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 A175506 Denominators of the antiharmonic means B of numbers k such that gcd(k, n) = 1 for numbers n >= 1 and k < n. %C A175506 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 A175506 a(n) = A175505(n) * A023896(n) / A053818(n). %t A175506 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 A175506 nonn %O A175506 1,3 %A A175506 _Jaroslav Krizek_, May 31 2010 %E A175506 More terms from _Robert G. Wilson v_, Jul 01 2010