A318952 a(n) = Sum_{d|n} (sigma(n) mod sigma(d)).

0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 5, 0, 0, 0, 5, 0, 6, 0, 6, 0, 0, 0, 8, 1, 0, 1, 10, 0, 0, 0, 4, 0, 0, 0, 31, 0, 0, 0, 12, 0, 0, 0, 12, 8, 0, 0, 30, 1, 6, 0, 16, 0, 6, 0, 9, 0, 0, 0, 30, 0, 0, 8, 13, 0, 0, 0, 18, 0, 0, 0, 67, 0, 0, 8, 22, 0, 0, 0, 40, 6, 0, 0

Offset

1,12

Links

Vaclav Kotesovec, Table of n, a(n) for n = 1..10000

Formula

a(A005117(n)) = 0.

a(A168363(n)) = 1.

Example

For n = 4; a(4) = (7 mod 1) + (7 mod 3) + (7 mod 7) = 0 + 1 + 0 = 1.

Mathematica

Table[Sum[Mod[DivisorSigma[1, n], DivisorSigma[1, d]], {d, Divisors[n]}], {n, 1, 100}] (* Vaclav Kotesovec, Sep 06 2018 *)

Prog

(Magma) [&+[SumOfDivisors(n) mod SumOfDivisors(d): d in Divisors(n)] : n in [1..1000]]
(PARI) a(n) = my(sn = sigma(n)); sumdiv(n, d, sn % sigma(d)); \\ Michel Marcus, Sep 06 2018

Crossrefs

Cf. A000203, A005117, A168363.

Sequence in context: A087935 A243829 A329639 * A089877 A278715 A333947

Adjacent sequences: A318949 A318950 A318951 * A318953 A318954 A318955

Keyword

nonn,look

Author

Jaroslav Krizek, Sep 05 2018

Status

approved