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
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}]
PROG
(PARI) a(n) = my(d=divisors(n^3)); vecmin(apply(abs, d - Vecrev(d))); \\ Michel Marcus, Feb 22 2021
CROSSREFS
KEYWORD
AUTHOR
Clark Kimberling, Apr 11 2017
STATUS
approved