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A285119 Min(|d(k+1-i) - d(i)|, for i = 1..k, where d(1),..,d(k) are the divisors of n^3. 1
0, 2, 6, 0, 20, 6, 42, 16, 0, 15, 110, 12, 156, 7, 30, 0, 272, 9, 342, 20, 84, 33, 506, 20, 0, 65, 162, 84, 812, 30, 930, 128, 176, 153, 70, 0, 1332, 209, 182, 6, 1640, 42, 1806, 110, 132, 345, 2162, 96, 0, 250, 170, 78, 2756, 162, 330, 56, 152, 609, 3422 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = 0 if and only if n is a square (A000290).

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..10000

FORMULA

a(n)=A056737(A000578(n)).

EXAMPLE

3^3 = 27 has divisors 1,3,9,27, so that k=4 and d(k+1-i) - d(i) ranges through {-26,-6,6,27}, so that a(3) = 6.

MATHEMATICA

f[n_] := f[n] = n^3; Table[Divisors[f[n]] - Reverse[Divisors[f[n]]], {n, 1, 10}]

Table[Min[Abs[Divisors[f[n]] - Reverse[Divisors[f[n]]]]], {n, 1, 100}]

CROSSREFS

Cf. A002378, A000578, A056737.

Sequence in context: A269943 A243015 A139717 * A202535 A138703 A106458

Adjacent sequences:  A285116 A285117 A285118 * A285120 A285121 A285122

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Apr 11 2017

STATUS

approved

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Last modified February 26 17:19 EST 2020. Contains 332293 sequences. (Running on oeis4.)