function [ n_data, x, y, fxy ] = beta_values ( n_data )

%% BETA_VALUES returns some values of the Beta function.
%
%  Discussion:
%
%    Beta(X,Y) = ( Gamma(X) * Gamma(Y) ) / Gamma(X+Y)
%
%    Both X and Y must be greater than 0.
%
%    In Mathematica, the function can be evaluated by:
%
%      Beta[X,Y]
%
%  Properties:
%
%    Beta(X,Y) = Beta(Y,X).
%    Beta(X,Y) = Integral ( 0 <= T <= 1 ) T**(X-1) (1-T)**(Y-1) dT.
%    Beta(X,Y) = Gamma(X) * Gamma(Y) / Gamma(X+Y)
%
%  Modified:
%
%    13 August 2004
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    Milton Abramowitz and Irene Stegun,
%    Handbook of Mathematical Functions,
%    US Department of Commerce, 1964.
%
%    Stephen Wolfram,
%    The Mathematica Book,
%    Fourth Edition,
%    Wolfram Media / Cambridge University Press, 1999.
%
%  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, Y, the arguments of the function.
%
%    Output, real FXY, the value of the function.
%
  n_max = 17;

  b_vec = [ ...
     0.5000000000000000E+01, ...
     0.2500000000000000E+01, ...
     0.1666666666666667E+01, ...
     0.1250000000000000E+01, ...
     0.5000000000000000E+01, ...
     0.2500000000000000E+01, ...
     0.1000000000000000E+01, ...
     0.1666666666666667E+00, ...
     0.3333333333333333E-01, ...
     0.7142857142857143E-02, ...
     0.1587301587301587E-02, ...
     0.2380952380952381E-01, ...
     0.5952380952380952E-02, ...
     0.1984126984126984E-02, ...
     0.7936507936507937E-03, ...
     0.3607503607503608E-03, ...
     0.8325008325008325E-04 ];

  x_vec = [ ...
     0.2E+00, ...
     0.4E+00, ...
     0.6E+00, ...
     0.8E+00, ...
     1.0E+00, ...
     1.0E+00, ...
     1.0E+00, ...
     2.0E+00, ...
     3.0E+00, ...
     4.0E+00, ...
     5.0E+00, ...
     6.0E+00, ...
     6.0E+00, ...
     6.0E+00, ...
     6.0E+00, ...
     6.0E+00, ...
     7.0E+00 ];

  y_vec = [ ...
     1.0E+00, ...
     1.0E+00, ...
     1.0E+00, ...
     1.0E+00, ...
     0.2E+00, ...
     0.4E+00, ...
     1.0E+00, ...
     2.0E+00, ...
     3.0E+00, ...
     4.0E+00, ...
     5.0E+00, ...
     2.0E+00, ...
     3.0E+00, ...
     4.0E+00, ...
     5.0E+00, ...
     6.0E+00, ...
     7.0E+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;
    y = 0.0;
    fxy = 0.0;
  else
    x = x_vec(n_data);
    y = y_vec(n_data);
    fxy = b_vec(n_data);
  end