MATHEMATICS · Subjective · AoPS · Mathematics · Sequences & Series · Sequences & Series
Problem
Let f(x) be a differentiable function satisfying f(x)+f(x+21)=1,∀x∈R and g(x)=∫0xf(t)dt. If g(1)=1, then the value of ∑n=2∞(∑k=1n(g(x+k2)−g(x+k))8) is.