3, -4, 7, -12, 19, ...
What is the next number in the sequence? What is the formula for the nth term of the sequence?
Thanks in advance!
Hi there, consider the following.
The absolute differences from each term follows a pattern $\displaystyle 1,3,5,7,\dots $
Every the sign of every second term alternates. And looking at the differences after breaking the patterns into positive and negative numbers you get are $\displaystyle 4,8,12,\dots$
Spoiler: