#!/usr/bin/ruby -w

=begin
/***************************************************************************
 *   Copyright (C) 2008 by Paul Lutus                                      *
 *   lutusp@arachnoid.com                                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
=end

def prime_test(v)
   return true  if(v == 2)
   return false if((v < 2) || (v % 2 == 0))
   testnum = 3
   while(((testsq = testnum * testnum) <= v) && (v % testnum != 0))
      testnum += 2;
   end
   return (testsq > v);
end

def euler_prime_function(x)
   return x*x + x + 41
end

0.upto(100) do |x|
   y = euler_prime_function(x)
   printf("%4d ",y)
   if prime_test(y)
      puts "is prime."
   else
      puts "is composite, hypothesis falsified."
      break
   end
end