a:  1 wallclock secs ( 0.75 usr +  0.00 sys =  0.75 CPU) @ 13368983.96/s (n=10000000)
         b:  0 wallclock secs ( 0.75 usr +  0.00 sys =  0.75 CPU) @ 13368983.96/s (n=10000000)
         c:  2 wallclock secs ( 1.70 usr +  0.00 sys =  1.70 CPU) @ 5878894.77/s (n=10000000)