A340145 Dirichlet inverse of A247074(x) = phi(x)/(Product_{primes p dividing x} gcd(p-1, x-1)).

1, -1, -1, -1, -1, 0, -1, -1, -2, -2, -1, 1, -1, -4, 0, -1, -1, 1, -1, 1, -1, -8, -1, 2, -4, -10, -4, 9, -1, 2, -1, -1, -3, -14, -4, 3, -1, -16, -4, 4, -1, 4, -1, 1, 4, -20, -1, 3, -6, -5, -6, 17, -1, 4, -8, -10, -7, -26, -1, 6, -1, -28, 0, -1, -1, 24, -1, 1, -9, 18, -1, 4, -1, -34, 1, 25, -13, 10, -1, 7, -8, -38, -1

Offset: 1

Author

Antti Karttunen, Dec 29 2020

Keywords

• sign

Links

• Antti Karttunen, Table of n, a(n) for n = 1..8191
• Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Crossrefs

Cf. A247074.

Cf. also A340142, A340144, A340146.

Programs

PARI

up_to = 65537;
A247074(n) = { my(f=factor(n)); eulerphi(f)/prod(i=1, #f~, gcd(f[i, 1]-1, n-1)); }; \\ From A247074
DirInverse(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = -sumdiv(n, d, if(dA247074(n)));
A340145(n) = v340145[n];