A054025 Sum of divisors of n read modulo (number of divisors of n).

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

Offset: 1

Author

Asher Auel, Jan 19 2000

Keywords

• nonn

Comments

a(A003601(n)) = 0; a(A049642(n)) > 0. [Reinhard Zumkeller, Jan 06 2012]

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000005, A000203.

Cf. A003601, A049642, A245656.

Programs

Haskell

import Data.List (genericIndex)
a054025 n = genericIndex a054025_list (n-1)
a054025_list = zipWith mod a000203_list a000005_list
-- Reinhard Zumkeller, Jul 28 2014, Jan 06 2012

Maple

with(numtheory): seq(sigma(i) mod tau(i),i=1..120);

Mathematica

Table[Mod[DivisorSigma[1,n],DivisorSigma[0,n]],{n,110}] (* Harvey P. Dale, Nov 16 2011 *)

PARI

vector(90, n, sigma(n) % numdiv(n)) \\ Michel Marcus, Aug 15 2015

Formula

a(n) = A000203(n) mod A000005(n), sigma(n) mod tau(n).