Every square-summable sequence $(a_{n})_{n}$ is represented by $a_{n}=\widehat{f}(4^n)$, where $\widehat{f}(i)$ is Fourier coefficient of continuous function $f$.
Where can I find proof of this theorem?
2026-03-30 21:09:55.1774904995
Square-summable sequence and Fourier series
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