Rhombic Dodecahedral Number					
				 
				
					
						
						 المؤلف:  
						Conway, J. H. and Guy, R. K.					
					
						
						 المصدر:  
						The Book of Numbers. New York: Springer-Verlag					
					
						
						 الجزء والصفحة:  
						...					
					
					
						
						24-12-2020
					
					
						
						925					
				 
				
				
				
				
				
				
				
				
				
			 
			
			
				
				Rhombic Dodecahedral Number
A figurate number which is constructed as a centered cube with a square pyramid appended to each face,
where 
 is a centered cube number and 
 is a square pyramidal number. The first few are 1, 15, 65, 175, 369, 671, ... (OEIS A005917). The generating function of the rhombic dodecahedral numbers is
	
		
			  | 
			
			 (3) 
			 | 
		
	
A related set of numbers is the number of cubes in the Haűy construction of the rhombic dodecahedron, given by
	
		
			  | 
			
			 (4) 
			 | 
		
	
for 
 an odd number. Re-indexing with 
 then gives
	
		
			  | 
			
			 (5) 
			 | 
		
	
giving the first few values 1, 33, 185, 553, 1233, ... (OEIS A046142).
REFERENCES:
Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, pp. 53-54, 1996.
Sloane, N. J. A. Sequences A005917/M4968 and A046142 in "The On-Line Encyclopedia of Integer Sequences."
				
				
					
					
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