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Search: id:A125057
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| A125057 |
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a(n) is the number of positive integers m such that floor(m/d(m)) = n, where d(m) is the number of positive divisors of m. |
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3
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| 5, 4, 9, 3, 7, 5, 6, 11, 7, 4, 8, 6, 9, 5, 4, 16, 7, 4, 8, 7, 11, 5, 10, 7, 7, 8, 7, 12, 9, 6, 10, 8, 8, 8, 10, 6, 4, 7, 7, 15, 8, 4, 11, 11, 8, 12, 7, 11, 7, 9, 8, 8, 12, 14, 8, 12, 8, 8, 11, 5, 14, 7, 7, 9, 5, 8, 4, 13, 7, 8, 12, 10, 6, 9, 14, 11, 9, 8, 9, 12, 13, 8, 8, 9, 9, 10, 7, 11, 14, 3, 10
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Is a(n) well-defined? Does every positive integer n equal floor(m/d(m)) for some m?
First occurrence of k>2 in A125057: 4,2,1,7,5,11,3,23,8,28,68,54,40,16,251,572,141,???,???,???,529,..., (630). - Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 11 2007.
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LINKS
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D. W. Wilson, Table of n, a(n) for n = 1..10000
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MATHEMATICA
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t = Table[Floor[n/DivisorSigma[0, n]], {n, 10^5}]; f[n_] := Length@Select[t, # == n &]; Array[f, 91] (* Robert G. Wilson v *)
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CROSSREFS
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Cf. A126888, A000005, A126889, A078709, A125056.
Sequence in context: A097943 A077142 A156057 this_sequence A021186 A092302 A002389
Adjacent sequences: A125054 A125055 A125056 this_sequence A125058 A125059 A125060
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KEYWORD
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nonn
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AUTHOR
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Hugo van der Sanden (hv(AT)crypt.org), Jan 09 2007
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EXTENSIONS
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Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 11 2007
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