The significance of the number patterns is simply that they are memorable.

Many numbers are seen every day. The unusual ones and the ones with personal meaning are the ones that are remembered. In your case, it would be the unusual ones you remember seeing. The Why You Start Seeing Certain Numbers Again and Again article talks more about that.

The more of a specific number or pattern of numbers a person sees repetitively, the more likely it is that the person will wonder if there's a special personal message or reason for it. It's a natural thing to need answers for things one doesn't understand.

Wondering if there's a reason creates a mystery. The subconscious mind feels compelled to solve mysteries, especially those with potential to affect a person's wellbeing. It tries to direct the conscious attention to anything that might be a clue to the mystery's solution, including the very same numbers.

Thus, as Why People See Certain Numbers All the Time explains, a person now notices those same number more often.

For numerology meanings of specific numbers, see the index to number meanings articles.