  In Type IIA compactified on a Calabi-Yau threefold, the genus zero and one
terms of the Gopakumar-Vafa (GV) formula describe F-terms that are related to
genus zero and one topological amplitudes. While for higher-genus terms
$\mathcal{F}_g, g\ge 2$, the contribution of a light hypermultiplet can be
computed via a sum over Kaluza-Klein harmonics, as has been shown in a recent
paper, for $g \leq 1$, the sum diverges and it is better to compute
$\mathcal{F}_0$ and $\mathcal{F}_1$ directly in five-dimensional field theory.
Such a computation is presented here.
