\[\boxed{\mathbf{231.}}\]
\[Каждое\ испытание\ либо\ У,\ \]
\[либо\ Н.\]
\[Общее\ число\ элементарных\ \]
\[событий:2^{n}.\]
\[\textbf{а)}\ 2^{n} = 16\]
\[2^{n} = 2^{4}\]
\[n = 4.\]
\[\textbf{б)}\ 2^{n} = 64\]
\[2^{n} = 2^{6}\]
\[n = 6.\]
\[\textbf{в)}\ 2^{n} = 256\]
\[2^{n} = 2^{8}\]
\[n = 8.\]
\[\textbf{г)}\ 2^{n} = 2048\]
\[2^{n} = 2^{11}\]
\[n = 11.\]
\[\textbf{д)}\ 2^{n} = 2^{m}\]
\[n = m.\]