(1)n(α+β+c+1)nn!Pn(α,β)(x;c)(α+β+2c+1)n(β+c+1)n==0n(n)(n+α+β+2c+1)(c+1)(β+c+1)(12x+12)F34(n,n++α+β+2c+1,β+c,cβ++c+1,+c+1,α+β+2c;1),