New Vacca-Type Rational Series for Euler's Constant and Its "Alternating" Analog ln(4/Pi)

Abstract

In math.CA/0211148 we observed that $\ln(4/ π)$ is an "alternating" analog of Euler's constant $γ$. Here we use the binary expansion of an integer to give a rational series for $\ln(4/ π)$ analogous to Vacca's series for $γ$. Also, using a known generalization of Vacca's series to other bases, we accelerate Addison's series for $γ$. Along the way, we give new proofs of Vacca's and Addison's formulas.