A160550 a(n) = A001065(n) mod A000005(n).

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

Offset: 1

Author

Ctibor O. Zizka, May 19 2009

Keywords

• easy
• nonn

Comments

A054022(n) for n > 1 gives the numbers k such that a(k) = 1.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384

Crossrefs

Cf. A000203, A000027, A000005, A054022, A001065, A003601, A140480.

Programs

Magma

[ (SumOfDivisors(n)-n) mod NumberOfDivisors(n): n in [1..105] ]; // Klaus Brockhaus, May 21 2009

Mathematica

Table[Mod[DivisorSigma[1,n]-n,DivisorSigma[0,n]],{n,110}] (* Harvey P. Dale, Jun 22 2013 *)

PARI

A160550(n)=lift(Mod(sigma(n)-n,numdiv(n))); \\ Michael B. Porter, Oct 13 2009

Extensions

Extended and comment edited by Klaus Brockhaus, May 21 2009