Summary: In 1949, F. W. J. Olver [Q. J. Mech. Appl. Math. 2, 452–457 (1949; Zbl 0034.41302)] established a transformation formula which converts a certain slowly convergent series into a rapidly convergent and easily computable form. The original (double) series occurs in aerodynamic interference calculations, and its numerical estimates have some practical importance. In this paper, the author revisits this double series from the point of view of analytic number theory, and shows the transformation property as a corollary of the Fourier-type expansion of a certain kind of non-holomorphic Eisenstein series by employing Mellin-Barnes integrals.