This really belongs with Lucky Spiral.

   C=: 13 :'1,1++/\4#>:1++2*i.y'
   C 6
1 3 5 7 9 13 17 21 25 31 37 43 49 57 65 73 81 91 101 111 121 133 145 157 169
   D1 C 6
741
   D2 C 6
825
   (D1 + D2) C 6
1566
   (D1 + D2) C 500
669171002

C 6 is the corners of 6 squares around 1

D1 and D2 are the diagonals

Linda

-----Original Message-----
From: [email protected] [mailto:programming-b
[email protected]] On Behalf Of Zsbán Ambrus
Sent: Monday, March 25, 2013 12:46 PM
To: [email protected]
Subject: Re: [Jprogramming] Lucky spiral

On Thu, Mar 21, 2013 at 9:24 PM, David Ward Lambert <[email protected]>
wrote:
> cw=:|:@:|. NB. clockwise matrix rotation assert (> 3 0 ; 4 1 ; 5 2) -: 
> cw i. 2 3
>
> spiral =: (, (>:@:(*/) + i.@:}.)@:$)@:cw assert (> 5 4 3 ; 6 1 2 ; 7 8 
> 9) -: (spiral^:4)1 1$1

Ah, look!  That looks like a new solution to the spiral problem we've
dicussed on this mailing list a while ago.  See the old thread near

http://www.jsoftware.com/pipermail/programming/2007-December/009009.html

Ambrus
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