Which series of numbers below is NOT an arithmetic sequence?

An Arithmetic sequence is a series of numbers in which each preceding term or number is added to or subtracted from the preceding number by the same constant number. <p>Let’s look at the following arithmetic sequence.</p>"
Example: 4, 8, 12, 16, 20, 24, 28, 32
In this series, the constant number is “4” and each preceding number has the number “4” added to it as follows:
4 + 4 = 8
+ 4 = 12
+ 4 = 16
+ 4 = 20
+ 4 = 24
+ 4 = 28
+ 4 = 32