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Sequence Number???
http://www.calcudoku.org/forum/viewtopic.php?f=24&t=607
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Author:  angel21  [ Mon Jul 07, 2014 12:15 pm ]
Post subject:  Sequence Number???

10 = 119 = 188 = 57 = 86 =125 = 24 = 53 = 62 = 11 = WHAT IS THE
>> NEXT NUMBER

Author:  firefly  [ Mon Jul 07, 2014 12:57 pm ]
Post subject:  Re: Sequence Number???

20 then 209

Author:  angel21  [ Mon Jul 07, 2014 5:48 pm ]
Post subject:  Re: Sequence Number???

Can you tell me how you worked it out please

Author:  firefly  [ Mon Jul 07, 2014 8:21 pm ]
Post subject:  Re: Sequence Number???

Assuming I have it correct, of course.

Looking for patterns, I noticed that the last digit of each number was in descending order (0, 9, 8, 7, 6...)
Looking at the remainder of each number, I noticed that they had a pattern as well. If the last digit of the number is x, then the first part of the number cycles through x-2, x+2, 2x+2. The only exceptions are where x-2 would fall below 1, in which case they seem to just use 1 instead.

So:
0 --> 0-2=-2 (special case) --> 1 & 0 --> 10
9 --> 9+2=11 --> 11 & 9 --> 119
8 --> 2(8)+2=18 --> 18 & 8 --> 188
7 --> 7-2=5 --> 5 & 7 --> 57
6 --> 6+2=8 --> 8 & 6 --> 86
5 --> 2(5)+2=12 --> 12 & 5 --> 125
4 --> 4-2=2 --> 2 & 4 --> 24
3 --> 3+2=5 --> 5 & 3 --> 53
2 --> 2(2)+2=6 --> 6 & 2 --> 62
1 --> 1-2=-1 (special case) --> 1 & 1 --> 11

Therefore:
0 --> 0+2=2 --> 2 & 0 --> 20
9 --> 2(9)+2=20 --> 20 & 9 --> 209
8 --> 8-2=6 --> 6 & 8 --> 68

etc.

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