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
FORMULA
MATHEMATICA
Table[Cyclotomic[Prime[n]^2, 2], {n, 7}] (* Arkadiusz Wesolowski, May 13 2012 *)
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