login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A106315 Harmonic residue of n. 15
0, 1, 2, 5, 4, 0, 6, 2, 1, 4, 10, 16, 12, 8, 12, 18, 16, 30, 18, 36, 20, 16, 22, 12, 13, 20, 28, 0, 28, 24, 30, 3, 36, 28, 44, 51, 36, 32, 44, 50, 40, 48, 42, 12, 36, 40, 46, 108, 33, 21, 60, 18, 52, 72, 4, 88, 68, 52, 58, 48, 60, 56, 66, 67, 8, 96, 66, 30, 84, 128, 70, 84, 72, 68, 78 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The harmonic residue is the remainder when n*d(n) is divided by sigma(n), where d(n) is the number of divisors of n and sigma(n) is the sum of the divisors of n. If n is perfect, the harmonic residue of n is 0.

LINKS

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

FORMULA

a(n) = A038040(n) - A000203(n) * A240471(n) . - Reinhard Zumkeller, Apr 06 2014

MAPLE

A106315 := proc(n)

    modp(n*numtheory[tau](n), numtheory[sigma](n)) ;

end proc:

seq(A106315(n), n=1..100) ; # R. J. Mathar, Jan 25 2017

MATHEMATICA

HarmonicResidue[n_]=Mod[n*DivisorSigma[0, n], DivisorSigma[1, n]]

PROG

(Haskell)

a106315 n = n * a000005 n `mod` a000203 n -- Reinhard Zumkeller, Apr 06 2014

CROSSREFS

Cf. A106316, A106317, A001599 (positions of zeros).

Cf. A000005, A000203.

Sequence in context: A191474 A199602 A324057 * A285295 A217563 A254881

Adjacent sequences:  A106312 A106313 A106314 * A106316 A106317 A106318

KEYWORD

nonn

AUTHOR

George J. Schaeffer (gschaeff(AT)andrew.cmu.edu), Apr 29 2005

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 20 12:16 EDT 2022. Contains 353871 sequences. (Running on oeis4.)