{1} ~连接~表[g=GraphData[{“Rook”,{n,n}}]-1+ParallelSum[Boole@ConnectedGraphQ@Subgraph[g,s],{s,Subsets@Range[n^2]}],{n,2,4}]
(*第二个程序:*)
b[n_,m_]:=和[(-1)^j*二项式[m,j]*(2^(m-j)-1)^n,{j,0,m}];
T[m_,n]:=T[m,n]=b[m,n]-和[T[i,j]*b[m-i,n-j]二项式[m-1,i-1]*二项式[n,j],{i,1,m-1},{j,1,n-1}];
a[n_]:=总和[二项式[n,i]*二项式[n,j]*T[i,j],{i,1,n},{j,1,n}];
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