function [ n_data, x, fx ] = stromgen_values ( n_data )

%*****************************************************************************80
%
%% STROMGEN_VALUES returns some values of the Stromgen function.
%
%  Discussion:
%
%    The function is defined by:
%
%      STROMGEN(X) = Integral ( 0 <= t <= X ) t^7 * exp(2*t) / (exp(t)-1)^3 dt
%
%    The data was reported by McLeod.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    19 September 2004
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    Allan McLeod,
%    Algorithm 757, MISCFUN: A software package to compute uncommon
%      special functions,
%    ACM Transactions on Mathematical Software,
%    Volume 22, Number 3, September 1996, pages 288-301.
%
%  Parameters:
%
%    Input/output, integer N_DATA.  The user sets N_DATA to 0 before the
%    first call.  On each call, the routine increments N_DATA by 1, and
%    returns the corresponding data; when there is no more data, the
%    output value of N_DATA will be 0 again.
%
%    Output, real X, the argument of the function.
%
%    Output, real FX, the value of the function.
%
  n_max = 20;

  fx_vec = [ ...
     0.21901065985698662316E-15, ...
     0.22481399438625244761E-12, ...
     0.23245019579558857124E-09, ...
     0.24719561475975007037E-06, ...
     0.28992610989833245669E-03, ...
     0.10698146390809715091E-01, ...
     0.89707650964424730705E-01, ...
     0.40049605719592888440E+00, ...
     0.30504104398079096598E+01, ...
     0.11367704858439426431E+02, ...
     0.12960679405324786954E+02, ...
     0.18548713944748505675E+02, ...
     0.27866273821903121400E+02, ...
     0.51963334071699323351E+02, ...
     0.10861016747891228129E+03, ...
     0.15378903316556621624E+03, ...
     0.19302665532558721516E+03, ...
     0.19636850166006541482E+03, ...
     0.19651946766008214217E+03, ...
     0.19651956920868316152E+03 ];

  x_vec = [ ...
       0.0019531250E+00, ...
       0.0078125000E+00, ...
       0.0312500000E+00, ...
       0.1250000000E+00, ...
       0.5000000000E+00, ...
       1.0000000000E+00, ...
       1.5000000000E+00, ...
       2.0000000000E+00, ...
       3.0000000000E+00, ...
       4.0000000000E+00, ...
       4.1250000000E+00, ...
       4.5000000000E+00, ...
       5.0000000000E+00, ...
       6.0000000000E+00, ...
       8.0000000000E+00, ...
      10.0000000000E+00, ...
      15.0000000000E+00, ...
      20.0000000000E+00, ...
      30.0000000000E+00, ...
      50.0000000000E+00 ]; 

  if ( n_data < 0 )
    n_data = 0;
  end

  n_data = n_data + 1;

  if ( n_max < n_data )
    n_data = 0;
    x = 0.0;
    fx = 0.0;
  else
    x = x_vec(n_data);
    fx = fx_vec(n_data);
  end

  return
end
