OFFSET
1,2
LINKS
Clark Kimberling, Table of n, a(n) for n = 1..10000
EXAMPLE
7(7+1)/2 = 28 has divisors 1,2,4,7,14,28, so that k=6 and d(k+1-i) - d(i) ranges through {-27,-12,-3,3,12,27}, so that a(7) = 3.
MATHEMATICA
f[n_] := f[n] = n(n+1)/2;
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
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Apr 11 2017
STATUS
approved