∑k=1n+1(n+1)!⁢(k-1)!(n-k+1)!⁢(-a-n)k⁢zn-k+1-∑k=0∞(a+n+1)k(n+2)k⁢k!⁢zn+k+1⁢(ln⁡z+ψ⁡(a+n+k+1)-ψ⁡(1+k)-ψ⁡(n+k+2)),