A125056 - OEIS

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A125056

a(n) is the largest positive integer such that floor(a(n)/d(a(n))) = n, where d(m) is the number of positive divisors of m.

6, 12, 30, 48, 60, 72, 120, 96, 144, 180, 140, 240, 216, 252, 360, 336, 420, 224, 312, 480, 504, 540, 378, 720, 600, 840, 660, 672, 352, 364, 756, 780, 1080, 960, 1260, 864, 594, 924, 936, 1440, 1320, 1680, 1050, 1056, 1092, 1120, 1512, 1560

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OFFSET

1,1

COMMENTS

We know the sequence is well-defined given the limit x/d(x) > 0.5*sqrt(x) from comments in A036763.

Does every positive integer n equal floor(m/d(m)) for some m?

LINKS

Hugo van der Sanden and D. W. Wilson, Table of n, a(n) for n = 1..10000

MATHEMATICA

t = Table[ Floor[ n / DivisorSigma[0, n]], {n, 10^5}]; f[n_] := Max@ Flatten@ Position[t, n]; Array[f, 51] (* Robert G. Wilson v, Jan 12 2007 *)

CROSSREFS

Cf. A126888, A000005, A126889, A078709, A125057.

Sequence in context: A126857 A161348 A071342 * A011987 A036690 A229746

Adjacent sequences: A125053 A125054 A125055 * A125057 A125058 A125059

KEYWORD

nonn

AUTHOR

Hugo van der Sanden, Jan 09 2007

STATUS

approved