∑ k = 0 ∞ [ 1 16 k ( 4 8 k + 1 − 2 8 k + 4 − 1 8 k + 5 − 1 8 k + 6 ) ] {\displaystyle \sum _{k=0}^{\infty }[{\frac {1}{16^{k}}}({\frac {4}{8k+1}}-{\frac {2}{8k+4}}-{\frac {1}{8k+5}}-{\frac {1}{8k+6}})]}
![{\displaystyle \sum _{k=0}^{\infty }[{\frac {1}{16^{k}}}({\frac {4}{8k+1}}-{\frac {2}{8k+4}}-{\frac {1}{8k+5}}-{\frac {1}{8k+6}})]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/f7466d134e5908a67b05a4a6234af6c7f0d9c87b)
