OFFSET
1,4
COMMENTS
Next term: a(24) = A084190(53130) > 10^91.
B-file goes up to n=59 because a(60) has 1503 digits. - Robert Israel, Sep 04 2019
LINKS
Robert Israel, Table of n, a(n) for n = 1..59
MAPLE
A084190:= n -> ilcm(op(map(`-`, numtheory:-divisors(n) minus {1}, 1))):
MATHEMATICA
b[n_] := LCM @@ (Rest[Divisors[n]] - 1);
a[n_] := If[n <= 2, 1, b@b@n];
Array[a, 59] (* Jean-François Alcover, Dec 16 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 18 2003
STATUS
approved