OFFSET
0,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 0..372
FORMULA
MATHEMATICA
Table[DivisorSigma[1, EulerPhi[2^n + 1]], {n, 0, 30}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jul 19 2004
EXTENSIONS
Offset changed to 0, a(0) prepended and three more terms added by Amiram Eldar, Jun 04 2024
STATUS
approved