Postgres SEQUENCEs and ROLLBACK

gistfile1.txt

$ psql
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psql (12.2 (Ubuntu 12.2-4), server 10.12 (Ubuntu 10.12-0ubuntu0.18.04.1))
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[local] nick@nick=# CREATE SEQUENCE test;
CREATE SEQUENCE
[local] nick@nick=# CREATE TABLE foo (id INT PRIMARY KEY DEFAULT nextval('test'));
CREATE TABLE
[local] nick@nick=# INSERT INTO foo VALUES(default);
INSERT 0 1
[local] nick@nick=# BEGIN;
BEGIN
[local] nick@nick=# INSERT INTO foo VALUES(default);
INSERT 0 1
[local] nick@nick=# INSERT INTO foo VALUES(default);
INSERT 0 1
[local] nick@nick=# SELECT * FROM foo;
 id
----
  1
  2
  3
(3 rows)

[local] nick@nick=# ROLLBACK;
ROLLBACK
[local] nick@nick=# INSERT INTO foo VALUES(default) RETURNING id;
 id
----
  4
(1 row)

INSERT 0 1
[local] nick@nick=# SELECT * FROM foo;
 id
----
  1
  4
(2 rows)