# T (n+1)(x)-2xT n(x)+T (n-1)(x)=0

The following formula holds for $n=0,1,2,\ldots$: $$T_{n+1}(x)-2xT_n(x)+T_{n-1}(x)=0,$$ where $T_n$ denotes Chebyshev polynomials of the first kind.