login
A069060
Product of divisors of 2^n + 1.
2
3, 5, 27, 17, 1089, 4225, 16641, 257, 69257922561, 1076890625, 4198401, 16785409, 67125249, 72075187834650625, 1238166730171084290520186881, 65537, 17180131329, 22301425772351053845871360015696103812890625, 274878955521
OFFSET
1,1
LINKS
FORMULA
a(n) = Product_{d|2^n + 1} d. - Wesley Ivan Hurt, Jan 23 2017
a(n) = A007955(A000051(n)). - Michel Marcus, Jan 24 2017
MATHEMATICA
Times@@Divisors[#]&/@(2^Range[20]+1) (* Harvey P. Dale, Mar 05 2020 *)
PROG
(PARI) a(n) = my(d=divisors(2^n+1)); prod(k=1, #d, d[k]); \\ Michel Marcus, Jan 24 2017
CROSSREFS
Sequence in context: A301315 A272148 A272224 * A273523 A307631 A307630
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Apr 04 2002
STATUS
approved