is postgresql identify would be continue in new version of PostgreSQL

Now I am use serial to generate table primary key in PostgreSQL 13, but today I found the ID jumps and not continue, it will waste many ids, I read the docs and found PostgreSQL add indentify as a SQL standard primary key generate. And the identify is continue? What should I do get a continue primary key id in PostgreSQL 13? I search from internet and recommand to use identify in new version of PostgreSQL but no one tell me the ID is continue.

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