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???
10/05/11 08:14
Modified:
  10/05/11 09:04

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#184045 - Many patterns complex/hard to enter
Responding to: ???'s previous message
You can't have two lines through a point. You can attach to the point and optionally continue to next point. But in the end, you have a "traveling salesman" that optionally don't have to visit all cities.

1 point = C(1,1)*1!
2 points = C(2,1)*1! + C(2,2)*2!
3 points = C(3,1)*1! + C(3,2)*2! + C(3,3)*3!
...

where C(n,m) is binominal coefficient = n! / (m!*(n-m)!)

1 point = 1*1 = 1
2 points = 2*1 + 1*2 = 4
3 points = 3*1 + 3*2 + 1*3 = 15
4 points = 4*1 + 6*2 + 4*6 + 1*24 = 64

size 1 = 1
size 2 = 4
size 3 = 15
size 4 = 64
size 5 = 325
size 6 = 1,956
size 7 = 13,699
size 8 = 109,600
size 9 = 986,409
size 10 = 9,864,100
size 11 = 108,505,111
size 12 = 1,302,061,344
size 13 = 16,926,797,485
size 14 = 236,975,164,804
size 15 = 3,554,627,472,075
size 16 = 56,874,039,553,216

The bad thing here is that while the combinations increases rapidly, many of them are very uncomfortable to enter. I wonder if the number of "good" combinations can be expressed in a good way.

Edit: corrected formula
Edit: Added evaluated results.

List of 14 messages in thread
TopicAuthorDate
A quick question            01/01/70 00:00      
   Many patterns complex/hard to enter            01/01/70 00:00      
      oohh            01/01/70 00:00      
   9 points grid (3x3) 4lines ?            01/01/70 00:00      
      Yes and no            01/01/70 00:00      
         3x3 grid in real life            01/01/70 00:00      
            Not at all - goal is security, not puzzle            01/01/70 00:00      
               Only one way to to connect 3x3 with 4 lines            01/01/70 00:00      
                  Stupid            01/01/70 00:00      
                     Stupid opinion            01/01/70 00:00      
                        Yes, I do know the solution            01/01/70 00:00      
                           Patterns ...            01/01/70 00:00      
                              No time. No acceleration. No lift. No finger outside screen.            01/01/70 00:00      
                                 Password Glyphs            01/01/70 00:00      

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