OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..350
EXAMPLE
The 4th primorial (210) has 16 divisors and 48 coprimes, so a(4) = 16 + 48 = 64.
MATHEMATICA
DivisorSigma[0, #]+EulerPhi[#]&/@Rest[FoldList[Times, 1, Prime[Range[20]]]] (* Harvey P. Dale, Sep 19 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved