If we want to represent the nth derivative of $\displaystyle (ax+b)^m$, then out of many we can write:

$\displaystyle \displaystyle f^{(n)}(x) = a^n(ax+b)^{m-n}\prod_{n=0}^{n-1}(m-n)$ (Lagrange's notation).

$\displaystyle \displaystyle \frac{d^ny}{dx^n} = a^n(ax+b)^{m-n}\prod_{n=0}^{n-1}(m-n)$ (Leibniz's notation).

But what notation do we use for representing the reverse — that is, for the nth integral of the RHS?