A054014 - OEIS

%I #10 Oct 27 2023 22:00:46

%S 0,0,0,2,0,1,0,2,0,3,0,3,0,1,0,4,0,2,0,3,2,1,0,3,2,3,0,3,0,1,0,0,2,3,

%T 0,0,0,1,0,1,0,5,0,3,2,1,0,5,1,0,0,3,0,1,0,7,2,3,0,11,0,1,4,6,2,5,0,3,

%U 2,1,0,2,0,3,0,3,2,1,0,5,4,3,0,7,2,1,0,3,0,11,0,3,2,1,0,11,0,0,2,8,0,1,0

%N Chowla function of n read modulo (the number of divisors of n).

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

%H Antti Karttunen, <a href="/A054014/b054014.txt">Table of n, a(n) for n = 1..16384</a>

%F a(n) = A048050(n) mod A000005(n).

%p with(numtheory): [seq((sigma(i)-i-1) mod tau(i),i=1..120)];

%t Array[Mod[DivisorSigma[1, #] - # - 1, DivisorSigma[0, #]] &, 103] (* _Michael De Vlieger_, Oct 30 2017 *)

%o (PARI) A054014(n) = ((sigma(n)-n-1) % numdiv(n)); \\ _Antti Karttunen_, Oct 30 2017

%Y Cf. A000005, A048050, A054013, A054015.

%K nonn

%O 1,4

%A _Asher Auel_, Jan 17 2000