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A103578
Number of divisors of m^2, where m is the smallest number with at least n divisors.
2
1, 3, 5, 9, 15, 15, 21, 21, 25, 27, 45, 45, 63, 63, 63, 63, 75, 75, 81, 81, 105, 105, 105, 105, 135, 135, 135, 135, 135, 135, 189, 189, 225, 225, 225, 225, 243, 243, 243, 243, 315, 315, 315, 315, 315, 315, 315, 315, 405, 405, 405, 405, 405, 405, 405, 405, 405
OFFSET
1,2
LINKS
FORMULA
a(n) = A000005((A061799(n))^2). - R. J. Mathar, Sep 01 2008
EXAMPLE
a(8) = 21 because smallest number with 8 divisors is 24, 24^2 = 576 and 576 has 21 divisors.
MATHEMATICA
a = {}; i = 1; For[n = 1, n < 60, n++, While[DivisorSigma[0, i] < n, i++ ]; AppendTo[a, DivisorSigma[0, i^2]]]; a (* Stefan Steinerberger, Aug 31 2008 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Edited by R. J. Mathar, Sep 01 2008, Dec 15 2008
Extended beyond a(8) by R. J. Mathar, Aug 31 2008
STATUS
approved