OFFSET
1,4
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537
FORMULA
a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A003415(n/d) * a(d).
PROG
(PARI)
up_to = 65537;
DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(d<n, v[n/d]*u[d], 0)))); (u) }; \\ Compute the Dirichlet inverse of the sequence given in input vector v.
A003415plusA063524(n) = if(n<=1, 1, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
v346241 = DirInverseCorrect(vector(up_to, n, A003415plusA063524(n)));
A346241(n) = v346241[n];
(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
memoA346241 = Map();
CROSSREFS
KEYWORD
sign
AUTHOR
Antti Karttunen, Jul 13 2021
STATUS
approved