Definite sum of a decreasing series

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can we find a closed form for following sum:

\begin{equation} \sum_{i=0}^{n} a^{i^2} = a^0 + a^1 + a^4+a^9 +...a^{n^2} \end{equation}

where $0<a<1$ , what if $n \rightarrow \infty$ ?