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A219364 Numbers such that the product of divisors of n is greater than the product of divisors of sigma(n). 2
4, 9, 16, 18, 25, 36, 48, 50, 64, 72, 80, 81, 100, 112, 144, 162, 192, 200, 208, 225, 240, 256, 288, 289, 300, 320, 324, 336, 400, 432, 441, 448, 450, 468, 484, 512, 576, 578, 592, 624, 625, 648, 676, 704, 720, 729, 768, 784, 800, 832, 882, 900, 960, 976 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

That is, numbers satisfying A007955(n) > A007955(A000203(n)).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

F. Luca, On the product of divisors of n and sigma(n), J. Inequal. Pure Appl. Math., Volume 4, Issue 2, Article 46, 2003.

MATHEMATICA

Select[Range[1000], Times @@ Divisors[#] > Times @@ Divisors[DivisorSigma[1, #]] &] (* T. D. Noe, Nov 19 2012 *)

PROG

(PARI) A007955(n)=if(issquare(n, &n), n^numdiv(n^2), n^(numdiv(n)/2))

is(n)=A007955(n)>A007955(sigma(n)) \\ Charles R Greathouse IV, Feb 04 2013

CROSSREFS

Cf. A000203, A007955.

Sequence in context: A102646 A104021 A073804 * A195212 A332443 A313323

Adjacent sequences:  A219361 A219362 A219363 * A219365 A219366 A219367

KEYWORD

nonn,easy

AUTHOR

Michel Marcus, Nov 19 2012

STATUS

approved

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Last modified July 12 19:35 EDT 2020. Contains 335668 sequences. (Running on oeis4.)