A054015 a(n) is Chowla function of n read modulo (number of proper divisors of n), a(1) = 0 by convention.

0, 0, 0, 0, 0, 2, 0, 0, 1, 1, 0, 0, 0, 0, 2, 2, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 2, 0, 6, 0, 0, 2, 1, 0, 6, 0, 0, 1, 0, 0, 4, 0, 4, 2, 1, 0, 3, 1, 2, 2, 0, 0, 2, 1, 0, 1, 1, 0, 8, 0, 0, 0, 2, 0, 0, 0, 2, 2, 3, 0, 1, 0, 0, 3, 3, 0, 5, 0, 6, 3, 1, 0, 7, 1, 0, 2, 0, 0, 0, 2, 0, 1, 1, 0, 1, 0, 2, 1, 4, 0, 1, 0, 0, 2

Offset: 1

Author

Asher Auel, Jan 17 2000

Keywords

• nonn

Comments

Chowla's function (A048050) = sum of divisors of n except 1 and n.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384
• Index entries for sequences related to sums of divisors

Crossrefs

Cf. A032741, A048050, A054013, A054014.

Programs

Maple

with(numtheory): [seq((sigma(i)-i-1) mod (tau(i)-1),i=2..120);#i>1

PARI

A054015(n) = if(1==n,0,((sigma(n)-n-1) % (numdiv(n)-1))); \\ Antti Karttunen, Oct 20 2017

Formula

a(1) = 0; for n > 1, a(n) = A048050(n) mod A032741(n).

Extensions

Description clarified by Antti Karttunen, Oct 20 2017