  We investigate planetary accretion that starts from equal-mass planetesimals
using an analytic theory and numerical simulations. We particularly focus on
how the planetary mass $M_{\rm oli}$ at the onset of oligarchic growth depends
on the initial mass $m_0$ of a planetesimal. Oligarchic growth commences when
the velocity dispersion relative to the Hill velocity of the protoplanet takes
its minimum. We find that if $m_0$ is small enough, this normalized velocity
dispersion becomes as low as unity during the intermediate stage between the
runaway and oligarchic growth stages. In this case, $M_{\rm oli}$ is
independent of $m_0$. If $m_0$ is large, on the other hand, oligarchic growth
commences directly after runaway growth, and $M_{\rm oli} \propto m_0^{3/7}$.
The planetary mass $M_{\rm oli}$ for the solid surface density of the Minimum
Mass Solar Nebula is close to the masses of the dwarf planets in a reasonable
range of $m_0$. This indicates that they are likely to be the largest remnant
planetesimals that failed to become planets. The power-law exponent $q$ of the
differential mass distribution of remnant planetesimals is typically $-2.0$ and
$-2.7$ to $-2.5$ for small and large $m_0$. The slope, $q \simeq -2.7$, and the
bump at $10^{21}$ g (or 50 km in radius) for the mass distribution of hot
Kuiper belt objects are reproduced if $m_0$ is the bump mass. On the other
hand, small initial planetesimals with $m_0 \sim 10^{13}$ g or less are favored
to explain the slope of large asteroids, $q \simeq -2.0$, while the bump at
$10^{21}$ g can be reproduced by introducing a small number of asteroid seeds
each with mass of $10^{19} $ g.
