main =>
  Gamma = 0.577215664901532860606512090082402,
  println(gamma=Gamma),
  member(N, 1..23),
  G = gamma(N),
  println([n=N,g=G,diff=G-Gamma]),
  fail,
  nl.

gamma(N) = Gamma =>
  Gamma = 1/2 - 1/3,
  foreach(I in 2..N)
    Power = 2**I,
    Sign = -1,
    Term = 0,
    foreach(Denominator in Power..(2*Power-1))
      Sign := Sign * -1,
      Term := Term + Sign / Denominator
    end,
    Gamma := Gamma + I*Term
  end.