What is the sum of binomial coefficients?

What is the sum of binomial coefficients?

Binomial formula: (a + b) ^ n = nc0 a ^ n + NC1 a ^ (n-1) * B +... NC (n-1) a * B ^ (n-1) + NCN B ^ n
It can be seen that when a = b = 1, the sum of polynomial coefficients = nc0 + NC1 +... + NC2 +... NC (n-1) +... NCN
So the sum of binomial coefficients = (1 + 1) ^ n = 2 ^ n