Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_11951237_1 (written_by VARCHAR, series__number VARCHAR)
### Question:
Who were the writers for series number 20?
### Answer:
SELECT written_by FROM table_11951237_1 WHERE series__number = 20