OFFSET
1,3
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1000
FORMULA
Moebius transform of A007955. - Andrew Howroyd, Jan 05 2020
EXAMPLE
For n = 4, A007955(n) = b(n): a(4) = b(1)*mu(4/1) + b(2)*mu(4/2) + b(4)*mu(4/4) = 1*0 + 2*(-1) + 8*1 = 6.
MATHEMATICA
a[n_] := Sum[ MoebiusMu[n/d] * Times @@ Divisors[d], {d, Divisors[n]} ]; Table[ a[n], {n, 1, 30} ] (* Jean-François Alcover, Jan 09 2013 *)
PROG
(PARI) a(n)={sumdiv(n, d, vecprod(divisors(d))*moebius(n/d))} \\ Andrew Howroyd, Jan 05 2020
(Magma) [&+[&*Divisors(d)*MoebiusMu(n div d):d in Divisors(n)]:n in [1..50]]; // Marius A. Burtea, Jan 05 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Apr 02 2010
EXTENSIONS
Terms a(31) and beyond from Andrew Howroyd, Jan 05 2020
STATUS
approved