# Math Help - the next number on the sequence

1. ## the next number on the sequence

Find the next number in the sequence 1, 3, 8, 16, ___

i've been using arithmetic sequence and even geometric sequence i could not get the answer because it does not have a constant difference and ratio. please do help me on this. from the book it says 27 is the next... but i could not get the pattern.

2. ## Re: the next number on the sequence

Find the differences between adjacent numbers and then find the differences between those differences.

3. ## Re: the next number on the sequence

Originally Posted by emakarov
Find the differences between adjacent numbers and then find the differences between those differences.
3-1 = 2
8-3 = 5 ... how is it done?

4. ## Re: the next number on the sequence

Originally Posted by rcs
3-1 = 2
8-3 = 5 ... how is it done?
Yes.

Code:
1   3   8   16   27
2   5   8    11
...
Now fill the third row.

5. ## Re: the next number on the sequence

Originally Posted by emakarov
Yes.

Code:
1   3   8   16   27
2   5   8    11
...
Now fill the third row.
thanks