通用公式:A(x)=1+x+3*x^2+13*x^3+65*x^4+350*x^5+1981*x^6+。。。
设A=g.f.A(x),则g.f.的对数等于级数:
log(A(x))=(1+x*A^2+x^2*A^4)*x*A+
(1+2^2*x*A^2+3^2*x2*A^4+2^2*x^3*A^6+x^4*A^8)*x^2*A^2/2+
(1+3^2*x*A^2+6^2*x^2*A^4+7^2*x ^3*A^6+6^2*x ^4*A^8+3^2*x^5*A^10+x^6*A^12)*x^3*A ^3/3+
(1+4^2*x*A^2+10^2*x2*A^4+16^2*x^3*A^6+19^2*x ^4*A^8+16^2*x^5*A^10+10^2*x ^6*A^12+4^2*x^7*A^14+x^8*A^16)*x^4*A ^4/4+
(1+5^2*x*A^2+15^2**x^2*A^4+30^2*x^3*A^6+45^2*x^4*A^8+51^2*x ^5*A^10+45^2*x ^6*A^12+30^2*x^7*A^14+15^2*x^8*A^16+5^2*x ^9*A^18+x^10*A^20)*x^5*A ^5/5+。。。