I want to say that the data is not like 154, 155, 156, 157, 158, 159 but can be 154, 156, 157, 159. How do I negate the word "consecutive"? I was not able to find it in the dictionary. I have found both variants but the resource is not very reliable.
COCA BNC nonconsecutive 22 0 non-consecutive 3 2 unconsecutive 1 0 inconsecutive 0 1
Do note that due to the relatively small corpus size, BNC won't always be clear in its verdict — as indeed it isn't too clear in this particular case —, so make sure to check both corpora. Especially when writing for an international audience.