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#1 Help Me ! » Permutations Calculator ~ Rules To Filter Repeated Pairs Of Numbers » 2014-06-24 11:29:06
- ClassicMan
- Replies: 1
This time I'm trying to use the 'Combinations and Permutations Calculator' to list permutations of numbers.
This is the calculator I'm using.
Combinations and Permutations Calculator
I want to list the permutations of the following.
9,8,7,6,5,4,3,2,-
(a) The - must appear once or twice in each permutation. For eg. [6,4,-] [-,-,3] [-5,2] and so on.
(b) Pairs of the numbers 9,8,7,6,5,4,3,2, must not be repeated. For eg [7,5,-] is good, but [5,7,-] is not allowed and so on. The - is unaffected by this and can appear repeatedly.
I entered the following into the calciulator.
Permutations without repetition (n=9, r=3)
Is order important: Yes
-,9,8,7,6,5,4,3,2
has 1 of: -,
This gave me almost the list I needed except that pairs of the numbers 9,8,7,6,5,4,3,2 were repeated. For eg, the list gave: [-,9,8] and [-.8,9], the [-,8,9] is not allowed. There were loads of other repeated pairs.
Could any of the rules be used to filter these repeated pairs of numbers and if so how would they be applied?
Many thanks.
#2 Re: Help Me ! » Combinations Calculator List To Reorder Highest To Lowest » 2014-06-24 10:10:33
..... For the issue of order, try entering the numbers in the correct order, ie., enter 9,9n,9b,9#,9+,3,...
That worked superbly. That's excellent, thanks very much. 
#3 Re: Help Me ! » Combinations Calculator List To Reorder Highest To Lowest » 2014-06-24 07:55:53
Hello anonimnystefy,
Thanks for your reply; it's much appreciated.
Which calculator are you using. I don't think we can help you by guessing what might and might not work.
The calculator I used was the 'Combinations and Permutations Calculator' on this website at the following link.
Maths Is fun Combinations and Permutations Calculator
Two questions:
What are you trying to calculate, because 125 does not seem to be correct for what you inserted...
I was trying to calculate combinations of the following:
2, 3, 9, 2n, 3n, 9n, 2b, 3b, 9b, 2#, 3#, 9#, 2+, 3+, 9
(a) I want each combintion to use three of the numbers.
(b) A number can only be used once in each combination
So I typed the following numbers and rules into the box. For the 'n' field in the calculator I entered 15 and for 'r' I entered 3.
2,3,9,2n,3n,9n,2b,3b,9b,2#,3#,9#,2+,3+,9+
no 2,2,2n no 2,2,2b no 2,2,2# no 2,2,2+
no 2,3,3n no 2,3,3b no 2,3,3# no 2,3,3+
no 2,9,9n no 2,9,9b no 2,9,9# no 2,9,9+
This gave me the 125 combinations but I was hoping for all the combinations to be ordered highest to lowest, eg. 9#,3n,2b instead of 3n,9#,2b.
On reflection now I don't think any of the rules will do this.
Thanks again for your help.
#4 Help Me ! » Combinations Calculator List To Reorder Highest To Lowest » 2014-06-23 07:51:45
- ClassicMan
- Replies: 5
Hello, I hope I've posted in the correct forum.
I've been using the online Combinations and Permutations Calculator and it's given me the results I almost need. I just can't get past the last step using 'Rules'. Here are my entries:
How many different numbers are possible? 15
How many numbers are used? 3
Is order of the numbers important? No
Can you repeat the number? No
The result gave me a list of 125 combinations which is wonderful. The only problem is that I need each combination to be shown highest to lowest number. I used some musical figuring such as: 9, 3b, 2# but the combination displayed as 3b, 9, 2#. Am I able to use any of the rules to change the display so that each combination is shown highest to lowest. For eg.
[3n, 2b, 9] [2#, 9n, 3] [3#, 2n, 9] would be rearranged to show: [9, 3n, 2b] [9n, 3, 2#] [9, 3#, 2n] so that all 124 combinations would follow the 9, 3, 2 pattern? How would I use the Rules to achieve this?
Many thanks.
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