We will introduce a class of m-times integrated Brownian motions.
The exact asymptotic expansions for the $L_2$-small ball
probabilities will be discussed for members of this class, of
which the usual m-times integrated Brownian motion is an
example. Another example will be what we call an Euler-integrated
Brownian motion. We will also find very sharp estimates for the
asymptotics of the eigenvalues of the covariance operator of
integrated Brownian motions and will, therefore, obtain
exact, not just logarithmic, asymptotics.