Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_5 ( no_in_series INTEGER, written_by VARCHAR, no_in_season VARCHAR )

### Question ###
What is the sum of the numbers in series written by sam meikle, which have 21 numbers in the season?

### Accurate SQL ###

SELECT SUM(no_in_series) FROM table_name_5 WHERE written_by = "sam meikle" AND no_in_season = 21