The 2008 Putnam exam has the following question for B2:
Let $F_0(x) = \ln x.$ For $n \geq 0$ and $x>0,$ let $F_{n+1} (x) = \int _0 ^xF_n(t) \, dt$. Evaluate $$\lim _{n \rightarrow \infty} \frac{n! F_n (1)}{\ln (n)}$$
In order to solve it, one must prove that $\lim _{n\rightarrow \infty} \frac{H_n}{\ln n} = 1$ where $H_n = 1 + 1/2 + 1/3 + \cdots + 1/n$ (the $n$th harmonic number). It's a pretty well known result that $$\lim _{n\rightarrow \infty} H_n - \ln n = \gamma \approx 0.577.$$Would one be allowed to use this result in the actual Putnam exam? Or would it be considered "trivializing the problem" and therefore cause a point deduction?