In the sequence of numbers, must the arrangement of numbers be regular? For example, is sequence 1,2,5,9,5,3,7,2,4,5,7 a sequence?

In the sequence of numbers, must the arrangement of numbers be regular? For example, is sequence 1,2,5,9,5,3,7,2,4,5,7 a sequence?

It's a sequence, but there are no rules. Not all sequences have to be regular