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								---
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								id: 5900f4c11000cf542c50ffd3
							 
						 
					
						
							
								
									
										
										
										
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								title: 'Problem 341: Golomb''s self-describing sequence'
							 
						 
					
						
							
								
									
										
										
										
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								challengeType: 5
							 
						 
					
						
							
								
									
										
										
										
											2019-08-05 09:17:33 -07:00 
										
									 
								 
							 
							
								
									
										 
								
							 
							
								 
							
							
								forumTopicId: 302000
							 
						 
					
						
							
								
									
										
										
										
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								dashedName: problem-341-golombs-self-describing-sequence
							 
						 
					
						
							
								
									
										
										
										
											2018-09-30 23:01:58 +01:00 
										
									 
								 
							 
							
								
							 
							
								 
							
							
								---
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								# --description--
  
						 
					
						
							
								
									
										
										
										
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								The Golomb's self-describing sequence ($G(n)$) is the only nondecreasing sequence of natural numbers such that $n$ appears exactly $G(n)$ times in the sequence. The values of $G(n)$ for the first few $n$ are
							 
						 
					
						
							
								
									
										
										
										
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								$$\begin{array}{c}
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								  n    &  1 &  2 &  3 &  4 &  5 &  6 &  7 &  8 &  9 &  10 &  11 &  12 &  13 &  14 &  15 &  \ldots \\\\
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								  G(n) &  1 &  2 &  2 &  3 &  3 &  4 &  4 &  4 &  5 &  5  &   5 &   6 &   6 &   6 &   6 &  \ldots
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								\end{array}$$
							 
						 
					
						
							
								
									
										
										
										
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								You are given that $G({10}^3) = 86$, $G({10}^6) = 6137$.
							 
						 
					
						
							
								
									
										
										
										
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								You are also given that $\sum G(n^3) = 153\\,506\\,976$ for $1 ≤ n <  {10}^3$.
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								Find $\sum G(n^3)$ for $1 ≤ n <  {10}^6$.
							 
						 
					
						
							
								
									
										
										
										
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								# --hints--
  
						 
					
						
							
								
									
										
										
										
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								`golombsSequence()`  should return `56098610614277016` . 
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
									
										
										
										
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								assert.strictEqual(golombsSequence(), 56098610614277016);
							 
						 
					
						
							
								
									
										
										
										
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								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								# --seed--
  
						 
					
						
							
								
									
										
										
										
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								## --seed-contents--
  
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
									
										
										
										
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								function golombsSequence() {
							 
						 
					
						
							
								
									
										
										
										
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								  return true;
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								}
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								golombsSequence();
							 
						 
					
						
							
								
									
										
										
										
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								```
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								
							 
						 
					
						
							
								
									
										
										
										
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								# --solutions--
  
						 
					
						
							
								
									
										
										
										
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								```js
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								// solution required
							 
						 
					
						
							
								
							 
							
								
							 
							
								 
							
							
								```