Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Week | Date | Opponent | Result | Attendance |
| --- | --- | --- | --- | --- |
| 1.0 | September 30, 1956 | at Chicago Cardinals | L 9–7 | 20966.0 |
| 2.0 | October 6, 1956 | at Pittsburgh Steelers | W 14–10 | 35398.0 |
| 3.0 | October 14, 1956 | New York Giants | L 21–9 | 60042.0 |
| 4.0 | October 21, 1956 | at Washington Redskins | L 20–9 | 23322.0 |
| 5.0 | October 28, 1956 | Pittsburgh Steelers | L 24–16 | 50358.0 |
| 6.0 | November 4, 1956 | at Green Bay Packers | W 24–7 | 28590.0 |
| 7.0 | November 11, 1956 | Baltimore Colts | L 21–7 | 42404.0 |
| 8.0 | November 18, 1956 | at Philadelphia Eagles | W 16–0 | 25894.0 |
| 9.0 | November 25, 1956 | Washington Redskins | L 20–17 | 22878.0 |
| 10.0 | December 2, 1956 | Philadelphia Eagles | W 17–14 | 20645.0 |
| 11.0 | December 9, 1956 | at New York Giants | W 24–7 | 27707.0 |
| 12.0 | December 16, 1956 | Chicago Cardinals | L 24–7 | 25312.0 |
Question:
What day did they play on week 4?
Answer:
October 21, 1956