Chudnovsky-Ramanujan type formulae for non-compact arithmetic triangle groups

We develop a conceptual and systematic method to derive Chudnovsky-Ramanujan type formulae for non-compact arithmetic triangle groups based on a generalization of a method of Chudnovsky and Chudnovsky; in particular, we use it to determine Ramanujan type series for $1/\pi$ whose coefficients are a product of a hypergeometric coefficient and a linear function of the summation index of the series.