\documentclass{article}
\usepackage[pdftex,active,tightpage]{preview}
\setlength\PreviewBorder{2mm}
\usepackage{pgfplots}

\begin{document}
\begin{preview}
\pgfplotsset{
    colormap={whitered}{
        color(0cm)=(white);
        color(1cm)=(orange!75!red)
    }
}
\begin{tikzpicture}
    \newcommand{\Pages}{250}
    \begin{axis}[
    colormap name=whitered,
    width=15cm,
    view={20}{25},
    enlargelimits=false,
    grid=major,
    domain=0:\Pages,
    y domain=1:\Pages,
    samples=16,
    xlabel=$p$, 
    ylabel=$C$,
    zlabel={$z$},
    colorbar,
    colorbar style={
        at={(-0.1,0)},
        anchor=south west,
        height=0.25*\pgfkeysvalueof{/pgfplots/parent axis height},
        title={$f(x,y)$}
    }
    ]
      \addplot3[surf] {(\Pages!/(x!*(\Pages-x)!)) * (1/y)^x * (1-1/y)^(\Pages-x)};
    \end{axis} 
\end{tikzpicture}
\end{preview}
\end{document}