How many odd numbers are in the 100th row of Pascal’s triangle?

How many entries in the 100th row of Pascal’s triangle
are divisible by 3? By 5?

When you divide a number by 2, the remainder is 0 or 1. Color
the entries in Pascal’s triangle according to this remainder.
You get a beautiful visual pattern. Can you explain it? Can you
generate the pattern on a computer?

What about the patterns you get when you divide by other numbers?
When you divide a number by 3, the remainder is 0, 1, or 2. Divide
the entries in Pascal’s triangle by 3 and color them according
to their remainder. Can you explain your picture?