|
|
A051156
|
|
a(n) = (2^p^2 - 1)/(2^p - 1) where p is the n-th prime.
|
|
8
|
|
|
5, 73, 1082401, 4432676798593, 1298708349570020393652962442872833, 91355004067076339167413824240109498970069278721, 7588608256743087977590500540116743445925584618982806531428980886590618779326218241
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Note that a(n) = Phi(p,2^p) or a(n) = Phi(p^2,2), where Phi(m,x) is the m-th cyclotomic polynomial and p is the n-th prime. - Thomas Ordowski, Feb 18 2014
|
|
LINKS
|
|
|
FORMULA
|
|
|
MATHEMATICA
|
Table[(2^Prime[n]^2-1)/(2^Prime[n]-1), {n, 10}] (* Harvey P. Dale, Apr 06 2019 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|