nmax=28;A[_]=0;Do[A[x_]=x+x^2 Exp[Sum[A[x^k]^4/(kx^(3k)),{k,1,nmax}]+O[x]^(nmax+1)//正常,nmax+1];系数列表[A[x],x]//静止
a[1]=a[2]=1;f[n]:=f[n]=和[a[k]a[n-k],{k,1,n-1}];g[n]:=g[n]=和[f[k]f[n-k],{k,1,n-1}];a[n]:=a[n]=(1/(n-2))和[Sum[dg[d+3],{d,Divisors[k]}]a[n-k],{k,1,n-2}];表[a[n],{n,1,28}]