CREATE TABLE table_15584067_7 (written_by VARCHAR2, us_viewers__million_ VARCHAR2)

Name who wrote the episode when the viewers was 1.81
SELECT written_by FROM table_15584067_7 WHERE us_viewers__million_ = "1.81"
SELECT "written_by" FROM "table_15584067_7" WHERE "1.81" = "us_viewers__million_"