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A051346 Numbers that can be written as k/d(k) in four or more ways, where d(k) = number of divisors of k. 8
11264, 14175, 28160, 44100, 46464, 51200, 64000, 82944, 95744, 96000, 107008, 109375, 109760, 116160, 129536, 151263, 162624, 163328, 174592, 192000, 208384, 224000, 230912, 239360, 242176, 242550, 246960, 264704, 267520, 281600, 286650, 290304, 298496, 302016 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..1000

EXAMPLE

From Jon E. Schoenfield, Feb 18 2021: (Start)

11264 is a term because it can be written as k/d(k) in four ways:

k = 360448: 360448/d(360448) = 360448/32 = 11264;

k = 585728: 585728/d(585728) = 585728/52 = 11264;

k = 630784: 630784/d(630784) = 630784/56 = 11264;

k = 1115136: 1115136/d(1115136) = 1115136/99 = 11264. (End)

MATHEMATICA

(* Assuming 3*10^5 <= k <= 3*10^8 *) ClearAll[cnt]; cnt[_] = 0; Do[ If[IntegerQ[n = k/DivisorSigma[0, k]], cnt[n]++; If[cnt[n] >= 4, Print[{n, k, cnt[n]}]]], {k, 3*10^5, 3*10^8}]; Select[Range[310000], cnt[#] >= 4 &] (* Jean-François Alcover, Sep 28 2012 *)

CROSSREFS

Cf. A000005, A051278, A051279, A051280, A217125, A217126, A217127.

Sequence in context: A031630 A064870 A051520 * A217125 A195654 A195649

Adjacent sequences: A051343 A051344 A051345 * A051347 A051348 A051349

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified February 7 13:59 EST 2023. Contains 360123 sequences. (Running on oeis4.)