1,3

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).

Table of n, a(n) for n=1..99.

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

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 *)

Sequence in context: A128262 A140414 A129514 * A211705 A010267 A023636

Adjacent sequences: A175503 A175504 A175505 * A175507 A175508 A175509

nonn

Jaroslav Krizek, May 31 2010

More terms from Robert G. Wilson v, Jul 01 2010

approved