Riddle

Solved
benoit1949 Posted messages 29 Status Membre -  
 benoit1949 -
A friend asked me this question:

1
11
21
1211
111221
312211
1311221

What is the logical sequence and why?
Thank you for enlightening me.

Benoit

4 réponses

via55 Posted messages 14730 Registration date   Status Membre Last intervention   2 755
 
Hello
1
11 we read the previous line there is one one so 11
21 the same: two ones so 21
1211 one two one one
111221 etc
312211
1311221
so sequence:
1113212211

QED

Best regards

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"Imagination is more important than knowledge." A. Einstein
0
benoit1949
 
Thank you for your promptness.
I don't have enough imagination to follow you....o))

The first two are fine, but for the third one, you start with a 2 because you add the previous line 1+1=2. And add a 1???

Would you be so kind as to detail it line by line for let's say, the first four lines?

I will visualize everything afterwards.

Thank you

Benoit
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benoit1949
 
Thank you, I appreciate it.

Benoit
0
aramir Posted messages 1131 Status Membre 226
 
OK, we’re going to continue then (sorry for the wait, I was away)

We start the next part with just one line that says 1

I analyze the first line "1", there is one 1 <=> in other words, there is "1 1", so I take 11 and write it on the line below/line 2.

I analyze the second line, the one we just wrote "11", there are two 1s <=> there are 2 1s, I write 21 below so
I analyze the 3rd line "21". More complex because there are several digits. This line starts with a 2, how many 2s are there? There is only one, so I write on a corner of my paper that there is "one 2" <=> "12", I move to the next digit (which is not a 2), it is a 1, how many 1s are there? There is only one, so I write on a corner of my paper that there is "one 1" <=> "11". Now I have reached the end of the line, so I write down what I found to create the next line, which is "11" and "11", I write these two pieces of information next to each other. The third line will therefore be "1211"

And now we go back to the mechanism, the line "1211" starts with a 1 => "11", the next digit is a "2", there is only one => "12". Followed by a new 2, there is one => "21". End of the line, so the next line will be "111221"

In short, we break each line into blocks of sequences of the same digit. We indicate the number of digits constituting the block and the digit constituting the block.
If we take letters again, xxxyyzxx it would give us

3x2y1z2x

Hoping this helps you
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benoit1949
 
Thank you, I see....

Benoit
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aramir Posted messages 1131 Status Membre 226
 
Hello,
in my opinion, it can be explained like this

1, on this line there is a 1 <=> there is 1 1
11, on this line there are two 1s <=> there are 2 1s
21, on this line there is a 2, then a 1 <=> there is 1 2 then 1 1
etc etc etc you take the first digit you look at the number of occurrences, you take the next different digit and do the same, etc etc etc

It goes back to middle school the last time I saw something like this ^^. A real time machine this "sequence".

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Raymond PENTIER Posted messages 58546 Registration date   Status Contributeur Last intervention   17 474
 
Hello to the three of you, I remind you that it is necessary to respect the purpose of each forum and to ask questions in the appropriate one.
Excel has nothing to do with this riddle, and the question should have been posted in Discussions & Opinions: Hobbies / Entertainment ...

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Retirement is great! Especially in the Caribbean ... :-)
☻ Raymond ♂
0
benoit1949
 
Sorry Raymond, we can't all be at the same level.. I'll pay attention next time.

Benoit
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