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A069057 Numbers k such that the numerator of Sum_{d|k} 1/d > 2k. 2
36, 100, 144, 324, 392, 400, 576, 784, 800, 900, 968, 1296, 1352, 1575, 1600, 1936, 2304, 2450, 2500, 2704, 2916, 3136, 3600, 3872, 4356, 4624, 5184, 5408, 5776, 6050, 6272, 6400, 7744, 8100, 8450, 8464, 9216, 9248, 10000, 10404, 10816, 11552, 11664 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Many terms in the sequence are squares: 6^2,10^2,12^2,18^2,20^2,24^2,28^2,30^2,36^2,40^2,44^2,48^2,50^2...

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

Select[Range[12000], Numerator[Total[1/Divisors@ #]] > 2 # &] (* Michael De Vlieger, May 04 2016 *)

PROG

(PARI) isok(n) = numerator(sigma(n)/n) > 2*n; \\ Michel Marcus, May 04 2016

CROSSREFS

Cf. A017665.

Sequence in context: A131605 A296204 A063734 * A062703 A043438 A044223

Adjacent sequences:  A069054 A069055 A069056 * A069058 A069059 A069060

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Apr 07 2002

STATUS

approved

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Last modified September 27 03:21 EDT 2020. Contains 337380 sequences. (Running on oeis4.)