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A046755 Numbers k such that d(k)^3 divides k. 5
1, 625, 6561, 21952, 32768, 64000, 98304, 117649, 163840, 229376, 360448, 425984, 557056, 622592, 753664, 950272, 1015808, 1212416, 1343488, 1362944, 1409024, 1540096, 1736704, 1933312, 1998848, 2195456, 2326528, 2392064, 2588672 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Proper subset of both A033950 and A046754. If two terms in the sequence are coprime then their product is also in the sequence.

LINKS

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

EXAMPLE

If k = 21952, d(k) = sigma(0,k) = 28. Its 3rd power is 21952, which divides k.

a(103) = 14385152 = (2^15)*439 with 32 divisors and 14385152/(32^3) = 439; 2^15*prime is a typical form of terms in the sequence that have 32 divisors.

MATHEMATICA

Select[ Range[ 1, 14500000 ], IntegerQ[ #/(DivisorSigma[ 0, # ])^3 ]& ]

CROSSREFS

Cf. A033950, A046754, A046756.

Sequence in context: A171995 A262798 A250431 * A016816 A046756 A143026

Adjacent sequences:  A046752 A046753 A046754 * A046756 A046757 A046758

KEYWORD

nonn

AUTHOR

Labos Elemer

STATUS

approved

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Last modified February 16 19:49 EST 2019. Contains 320167 sequences. (Running on oeis4.)