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A187680 a(n) = (product of divisors of n) mod (sum of divisors of n). 9
0, 2, 3, 1, 5, 0, 7, 4, 1, 10, 11, 20, 13, 4, 9, 1, 17, 21, 19, 20, 25, 16, 23, 36, 1, 4, 9, 0, 29, 0, 31, 8, 33, 22, 25, 83, 37, 4, 9, 40, 41, 48, 43, 8, 21, 28, 47, 88, 1, 8, 9, 76, 53, 96, 1, 16, 49, 34, 59, 120, 61, 4, 31, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A007955(n) mod A000203(n).

MAPLE

A187680 := proc(n) A007955(n) mod numtheory[sigma](n) ; end proc:

seq(A187680(n), n=1..120) ; # R. J. Mathar, Mar 17 2011

MATHEMATICA

Table[Mod[Times@@Divisors[n], DivisorSigma[1, n]], {n, 70}] (* Harvey P. Dale, May 23 2021 *)

PROG

(PARI) a(n) = my(d=divisors(n)); vecprod(d) % vecsum(d); \\ Michel Marcus, Jan 29 2019

CROSSREFS

Cf. A000203, A007955.

Sequence in context: A264638 A201737 A080063 * A328731 A140706 A200068

Adjacent sequences:  A187677 A187678 A187679 * A187681 A187682 A187683

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Mar 17 2011

STATUS

approved

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Last modified May 20 03:37 EDT 2022. Contains 353851 sequences. (Running on oeis4.)