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Generate a function from a list of numbers

I have a list of numbers x = [1, 11, 21, 1211, 111221,...], I need to find the 31st number in that list.
 
21,992
3,272
Hint: Look and say

Hint 2: 11 should not be seen as "eleven" but rather as individual ones.
 

pasmith

Homework Helper
1,735
408
I have a list of numbers x = [1, 11, 21, 1211, 111221,...], I need to find the 31st number in that list.
It could be anything. Truncating a sequence loses all information about subsequent terms.

Are you told how to construct the [itex]n[/itex]th term, given the values of previous terms? If so, you need to do that.
 
The actual question is to find the length of the 31st term.
 
Last edited:
21,992
3,272
The actual question is to find the length of the 31st term.
You need to recognize the pattern first. See Post #2.
 
100
15
Hint: The next term says something, quite literally, about the previous term.
 
76
10
The problem with this type of questions is that they have more than one answer in general. For this particular sequence we have 3 possibilities that can be found at OEIS.
 

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