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A056758 Numbers n for which d(n)^3 < n. 1
11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 65, 67, 69, 71, 73, 74, 77, 79, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 101, 103, 106, 107, 109, 111, 113, 115, 118, 119, 121, 122, 123, 125, 127, 129, 131, 133, 134, 137, 139, 141, 142, 143, 145, 146 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The complementary set (d^3 > n) is finite, albeit with very large terms. See also d(n)^2 < n, A035035.

The last number not in this sequence is 27935107200. - Charles R Greathouse IV, Feb 27 2017

LINKS

Table of n, a(n) for n=1..60.

Index entries for linear recurrences with constant coefficients, signature (2,-1).

FORMULA

d(n)^3 = A000005(n)^3 < n.

EXAMPLE

n=254, d(n)=4, d^3 = 64 < 254 so 254 is in the sequence.

PROG

(PARI) is(n)=numdiv(n)^3 < n \\ Charles R Greathouse IV, Feb 25 2017

CROSSREFS

Cf. A035033-A035035, A034884.

Sequence in context: A191599 A084374 A063193 * A322273 A096489 A008364

Adjacent sequences:  A056755 A056756 A056757 * A056759 A056760 A056761

KEYWORD

nonn,easy

AUTHOR

Labos Elemer, Aug 16 2000

STATUS

approved

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Last modified January 17 10:30 EST 2019. Contains 319218 sequences. (Running on oeis4.)