A181183 a(n) = sigma(tau(n)) (mod 2).

1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1

Offset: 1

Author

Jani Melik, Jan 26 2011

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537
• Index entries for characteristic functions
• Index entries for sequences computed from exponents in factorization of n

Crossrefs

Cf. A000035, A062069.

Programs

Maple

A181183:= n-> (numtheory[sigma](numtheory[tau](n)) mod 2):
seq (A181183(n), n=1..105);

Mathematica

Array[Mod[DivisorSigma[1, DivisorSigma[0, #]], 2] &, 105] (* Michael De Vlieger, Nov 18 2017 *)

PARI

A181183(n) = (sigma(numdiv(n))%2); \\ Antti Karttunen, Nov 18 2017

Formula

a(n) = A000035(A062069(n)). - Antti Karttunen, Nov 18 2017