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A160320 Numbers n for which sigma(n)/n = k+1/3 with integer k. 10
3, 12, 234, 1080, 6048, 6552, 435708, 4713984, 18506880, 36197280, 275890944, 299980800, 4138364160, 13286744064, 17827568640, 30600708096, 459010621440, 2198278051200, 2567400675840, 3321402084000, 4959751305600, 295185198672000, 1217745604232064 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..23.

EXAMPLE

a(1)=3 since sigma(3)/3=(1+3)/3=1+1/3.

a(2)=12 since sigma(12)/12=(1+2+3+4+6+12)/12=28/12=7/3=2+1/3.

PROG

(PARI) is(n)=denominator(sigma(n, -1)-1/3)==1 \\ Charles R Greathouse IV, Mar 09 2014

CROSSREFS

Cf. A160321 (sigma(n)/n=k+2/3), A159907 (sigma(n)/n=k+1/2).

Sequence in context: A089428 A211892 A063801 * A321603 A297564 A280086

Adjacent sequences:  A160317 A160318 A160319 * A160321 A160322 A160323

KEYWORD

nonn

AUTHOR

J.C. Klein (hklein(AT)planet.nl), May 08 2009

EXTENSIONS

a(11)-a(16) from Donovan Johnson, May 26 2009

a(17)-a(23) from Michel Marcus, Sep 21 2012

STATUS

approved

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Last modified January 22 22:16 EST 2020. Contains 331166 sequences. (Running on oeis4.)