[VA] SRC#002- Almost integers and other beasties

[Albert Chan]

Hi, Gerson W. Barbosa

Your code might be shortened and faster by removing (-1)^k factor.
Since it pre-calculated iterations required, summing backwards may be more accurate.
Example: With 4 digits precision, sum 4 terms,

t = |sum| = 1 - 1/(2*3) + 1/(3*7) - 1/(4*15)

Steps:
t = 0
t = 1/60 - t = 0.01667
t = 1/21 - t = 0.04762 - t = 0.03095
t = 1/6 - t = 0.1667 - t = 0.1358
t = 1 - t = 0.8642