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								---
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								id: 5900f4491000cf542c50ff5c
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								title: 'Problem 221: Alexandrian Integers'
							 
						 
					
						
							
								
									
										
										
										
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								challengeType: 5
							 
						 
					
						
							
								
									
										
										
										
											2019-08-05 09:17:33 -07:00 
										
									 
								 
							 
							
								
									
										 
									 
								
							 
							
								 
							 
							
								
									
								 
							
							
								forumTopicId: 301864
							 
						 
					
						
							
								
									
										
										
										
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								dashedName: problem-221-alexandrian-integers
							 
						 
					
						
							
								
									
										
										
										
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								---
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								# --description--
 
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								We shall call a positive integer A an "Alexandrian integer", if there exist integers p, q, r such that: A = p · q · r and 1/A = 1/p + 1/q + 1/r
							 
						 
					
						
							
								
									
										
										
										
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								<!--  TODO Use MathJax  --> 
							 
						 
					
						
							
								
									
										
										
										
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								For example, 630 is an Alexandrian integer (p = 5, q = −  7, r = −  18). In fact, 630 is the 6th Alexandrian integer, the first 6 Alexandrian integers being: 6, 42, 120, 156, 420 and 630.
							 
						 
					
						
							
								
									
										
										
										
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								Find the 150000th Alexandrian integer.
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								# --hints--
 
							 
						 
					
						
							
								
									
										
										
										
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								`euler221()`  should return 1884161251122450.
							 
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								assert.strictEqual(euler221(), 1884161251122450);
							 
						 
					
						
							
								
									
										
										
										
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								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								# --seed--
 
							 
						 
					
						
							
								
									
										
										
										
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								## --seed-contents--
 
							 
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								function euler221() {
							 
						 
					
						
							
								
									
										
										
										
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								  return true;
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								}
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								euler221();
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								# --solutions--
 
							 
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								// solution required
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							 
							
								
									
								 
							
							
								```