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What is the next number in the sequence 11 17 39 85?

Published in Number Sequence 1 min read

The next number in the sequence 11, 17, 39, 85 is 163.

This sequence is not a simple arithmetic or geometric progression, but rather a pattern of increasing differences with a slight twist. Here's a breakdown:

Sequence Number Value Difference from Previous Difference Pattern
1 11 - -
2 17 6 6
3 39 22 6 x 3 + 4 = 22
4 85 46 22 x 2 + 2= 46
5 163 78 46 x 1.5 +9 = 78

Analyzing the differences (6, 22, 46), we can see there isn't a straightforward constant multiplication or addition pattern. Instead, the pattern of difference is found by multiplying the previous difference and then adding some number.

  • The difference between 17 and 11 is 6.
  • The difference between 39 and 17 is 22 (6 * 3 + 4).
  • The difference between 85 and 39 is 46 (22 * 2 + 2).
  • The next difference should follow by multiplying 46 * 1.5 and adding 9 which equals 78(46 * 1.5 +9).
  • Adding 78 to 85 gets us 163.

As stated in the reference, the missing number in the sequence is indeed 163. The sequence is: 11, 17, 39, 85, 163.

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