OFFSET
1,4
FORMULA
G.f.: -Sum_{k>=2} mu(k) * x^k * (1 + x^k) / (1 - x^k)^2. - Ilya Gutkovskiy, Sep 14 2021
MATHEMATICA
g[n_] := Table[ #^2 &[m], {m, 1, n + 1}] - FoldList[Plus, 1, 2 Array[EulerPhi, n, 2]] - Most[Flatten[ Append[{0}, Table[ #^2 &[m], {m, 1, n + 1}] - FoldList[Plus, 1, 2 Array[EulerPhi, n, 2]]]]]; g[80]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gregg Whisler, Jun 25 2008
EXTENSIONS
More terms from Robert G. Wilson v, Jan 17 2011
STATUS
approved