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A319296 a(n) = (Sum_{d|n} (sigma(d))) mod sigma(n). 4
0, 1, 1, 4, 1, 8, 1, 11, 5, 10, 1, 27, 1, 12, 11, 26, 1, 33, 1, 35, 13, 16, 1, 10, 7, 18, 18, 43, 1, 68, 1, 57, 17, 22, 15, 16, 1, 24, 19, 2, 1, 84, 1, 59, 48, 28, 1, 37, 9, 59, 23, 67, 1, 112, 19, 114, 25, 34, 1, 49, 1, 36, 58, 120, 21, 116, 1, 83, 29, 108 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

a(n) = A007429(n) mod A000203(n).

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

FORMULA

a(A221219(n)) = 0.

a(A000040(n)) = 1; the only composite number < 2*10^6 with a(n) = 1 is 636.

a(n) = n only for numbers 4, 10 and 96 < 3000000.

EXAMPLE

For n = 4; a(4) = ((sigma(1) + sigma(2) + sigma(4)) mod sigma(4) = (1+3+7) mod 7 = 11 mod 7 = 4.

MATHEMATICA

Table[Mod[Sum[DivisorSigma[1, d], {d, Divisors[n]}], DivisorSigma[1, n]], {n, 1, 100}] (* Vaclav Kotesovec, Sep 26 2018 *)

PROG

(MAGMA) [&+[SumOfDivisors(d): d in Divisors(n)] mod  SumOfDivisors(n): n in [1..1000]]

(PARI) A319296(n) = (sumdiv(n, d, sigma(d))%sigma(n)); \\ Antti Karttunen, Sep 16 2018

CROSSREFS

Cf. A000203, A007429, A221219.

Sequence in context: A040019 A240776 A019768 * A211779 A318445 A158496

Adjacent sequences:  A319293 A319294 A319295 * A319298 A319299 A319300

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Sep 16 2018

STATUS

approved

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Last modified April 21 22:12 EDT 2019. Contains 322328 sequences. (Running on oeis4.)