1. Obviously a0>a1>a2>⋯. Since ak−ak+1=1−ak+11, we have an=a0+(a1−a0)+⋯+(an−an−1)=1994−n+a0+11+⋯+an−1+11> 1994−n. Also, for 1≤n≤998,
a0+11+⋯+an−1+11<1.
Hence,
an<1995−n.
For 999≤n≤1993,
a0+11+⋯+an−1+11>1.
Thus,
an<1994−n.
For n=1994,
a0+11+⋯+a1993+11=1.
Therefore,
a1994=0.
For n≥1995,
a0+11+⋯+an−1+11>1.
Hence,
an<1994−n.
In summary, for 1≤n≤998,
⌊an⌋=1994−n.