function a = r8sto_dif2 ( n )

%*****************************************************************************80
%
%% R8STO_DIF2 sets the second difference as an R8STO matrix.
%
%  Discussion:
%
%    The R8STO storage format is used for a symmetric Toeplitz matrix.
%    It stores the N elements of the first row.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    27 September 2015
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, integer N, the order of the matrix.
%    N must be positive.
%
%    Output, real A(N), the R8STO matrix.
%
  a = zeros ( n, 1 );
  a(1) = 2.0;
  a(2) = -1.0;

  return
end
