# the next number on the sequence

• Dec 1st 2012, 03:50 AM
rcs
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.
• Dec 1st 2012, 03:56 AM
emakarov
Re: the next number on the sequence
Find the differences between adjacent numbers and then find the differences between those differences.
• Dec 1st 2012, 03:59 AM
rcs
Re: the next number on the sequence
Quote:

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?
• Dec 1st 2012, 04:02 AM
emakarov
Re: the next number on the sequence
Quote:

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.
• Dec 1st 2012, 04:09 AM
rcs
Re: the next number on the sequence
Quote:

Originally Posted by emakarov
Yes.

Code:

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

thanks