>>5
I[n] = ∫[-1,1] (x-1)^4(x+1)^n dx
= (1/5)[(x-1)^5 (x+1)^n]_[-1,1] - (n/5)∫[-1,1] (x-1)^5(x+1)^(n-1) dx
= -(n/5)∫[-1,1] (x-1)^5(x+1)^(n-1) dx
= -(n/5)∫[-1,1] {(x-1)^4(x+1)^n - 2(x-1)^4(x+1)^(n-1)} dx
= -(n/5)(I[n] - 2I[n-1])

I[n] = (2n/(n+5))I[n-1]
= (4n(n-1)/(n+4)(n+5))I[n-2]