A Row of Pascal's Triangle

Pascal's triangle starts with row 0 equal to [1]. Every next row begins and ends with 1, and each inner value is the sum of the two values above it:

row 0:        1
row 1:       1 1
row 2:      1 2 1
row 3:     1 3 3 1
row 4:    1 4 6 4 1

Return row number row as a list. The values get big, and Python integers handle that exactly.

Examples

Example 1

Input:

pascal_row(4)

Output:

[1, 4, 6, 4, 1]

Example 2

Input:

pascal_row(0)

Output:

[1]

Constraints

• 0 <= row <= 1000