On a conjectural series of Sun for the mathematical constant β(4).

Let $ \beta (z) $ β (z) be the Dirichlet beta function. Series for $ \beta (4) $ β (4) are very rare in the historical development of mathematics. With the help of the operator method and a transformation formula for hypergeometric series, we prove a surprising conjectural series of Z.-W Sun for the mathematical constant $ \beta (4) $ β (4). Furthermore, we find five new series for the same constant in this paper. [ABSTRACT FROM AUTHOR]