-- The iterated logarithm lg*(n) --
  n =          1  lg*(n) = 0
  n =          2  lg*(n) = 1
  n =          4  lg*(n) = 2
  n =         16  lg*(n) = 3
  n =      65536  lg*(n) = 4
  n =    2^65536  lg*(n) = 5 (by definition, one more than lg*(65536))

-- Stirling: n! vs sqrt(2 pi n) (n/e)^n --
  n =   1  n! =   1.000000e+00  Stirling =   9.221370e-01  ratio = 1.084438
  n =   5  n! =   1.200000e+02  Stirling =   1.180192e+02  ratio = 1.016784
  n =  10  n! =   3.628800e+06  Stirling =   3.598696e+06  ratio = 1.008365
  n =  15  n! =   1.307674e+12  Stirling =   1.300431e+12  ratio = 1.005570
  n =  20  n! =   2.432902e+18  Stirling =   2.422787e+18  ratio = 1.004175
