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A035033 Numbers n such that n <= d(n)^2, where d() = number of divisors (A000005). 18
1, 2, 3, 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 24, 28, 30, 32, 36, 40, 42, 48, 54, 56, 60, 72, 80, 84, 90, 96, 108, 120, 126, 132, 140, 144, 168, 180, 192, 210, 216, 240, 252, 288, 300, 336, 360, 420, 480, 504, 540, 720, 840, 1260 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..54.

MATHEMATICA

Select[Range[1300], #<=DivisorSigma[0, #]^2&] (* Harvey P. Dale, Mar 16 2012 *)

PROG

(PARI) is(n)=numdiv(n)^2>=n \\ Charles R Greathouse IV, Aug 03 2012

CROSSREFS

Cf. A000005, A035034, A035035, A033950, A036763, A034884, A273323.

Sequence in context: A225730 A256389 A225729 * A054220 A196277 A280196

Adjacent sequences:  A035030 A035031 A035032 * A035034 A035035 A035036

KEYWORD

nonn,fini,full

AUTHOR

Erich Friedman, Labos Elemer

STATUS

approved

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Last modified April 19 16:18 EDT 2019. Contains 322282 sequences. (Running on oeis4.)