Odd Power

An odd power is a number of the form  for  an integer and  a positive odd integer. The first few odd powers are 1, 8, 27, 32, 64, 125, 128, 216, 243, 343, 512, ... (OEIS A070265). Amazingly, the double series of reciprocals of the odd powers that are congruent to 3 (mod 4) is given by

REFERENCES:

Sloane, N. J. A. Sequence A070265 in "The On-Line Encyclopedia of Integer Sequences."