

A274641


Counterclockwise square spiral constructed by greedy algorithm, so that each row, column, and diagonal contains distinct numbers. Start with 0 (so in this version a(n) = A274640(n)  1).


33



0, 1, 2, 3, 1, 2, 3, 4, 5, 0, 3, 5, 1, 0, 5, 4, 2, 0, 4, 1, 5, 0, 1, 3, 4, 2, 6, 7, 4, 3, 8, 6, 7, 2, 9, 10, 3, 6, 7, 5, 2, 8, 4, 6, 7, 8, 9, 10, 11, 5, 7, 8, 10, 9, 11, 12, 6, 5, 9, 8, 11, 12, 13, 14, 7, 1, 8, 11, 6, 9, 10, 12, 13, 9, 8, 5, 12, 4, 2, 14, 15, 6, 0, 9, 12, 11, 13, 10, 14, 2, 7, 4, 0, 11, 10, 13, 6, 3, 1, 15, 8, 16, 0, 7, 10
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OFFSET

0,3


COMMENTS

See A274640 for further information.
Presumably every row, column, and diagonal is a permutation of the natural numbers, but is there a proof?  N. J. A. Sloane, Jul 10 2016


LINKS



EXAMPLE

The spiral begins:
.
815136131011047
 
16 7141312118956 2
   
0 1 31092768 12 14
     
7 8 6 24501 3 11 10
       
10 11 7 0 132 5 4 9 13
         
14 6 5 4 2 01 3 7 10 11
        
13 9 2 1 3450 6 8 12
      
6 10 8 501342 7 9
    
3 12 4678910115 0
  
11 13985124214156

9140111571312101716
.
(End)


CROSSREFS

Cf. A274640 (if start with 1 at center), A324481 (position of first n).


KEYWORD

nonn


AUTHOR



STATUS

approved



