To calculate delta V of low thrust ion spirals, you subtract speed of departure orbit from speed of destination orbit. See Mark Adler's explanation.
Time spent is delta V/acceleration.
LEO is ~7.7 km/s.
At the edge of earth's Hill sphere, escape velocity is about .7 km/s
So 7 km/s to climb out of earth's gravity well from LEO.
Earth heliocentric orbit is about 30 km/s
Mars heliocentric orbit is 24 km/s.
So 6 km/s to get from earth to Mars heliocentric orbits
Escape velocity at the edge of Mars Hill Sphere is .3 km/s
Low Mars Orbit velocity is 3.4 km/s
So about 3 km/s to climb down Mars gravity well.
7 + 6 + 3 is 16 km/s. 16 km/s to get from LEO to LMO via ion engines. In meters, that's about 16,000 meters/sec.
(16,000 m/s) / (.0004 m/s^2) = 40 million seconds = 463 days.
For the other accelerations, the 1 A.U. to 1.52 A.U. heliocentric trip takes less time than Hohmann and delta V will be higher than 6 km/s. I can't give you the times for the other accelerations without investing more time and effort than I can afford at the moment.
As you can see, climbing in and out of planetary gravity wells takes more delta V (and therefore time) than doing the heliocentric transfer orbit. Which is why I advocate berthing a Hermes like craft at EML2 between trips. At the Mars end of the trip, Deimos might be good place to berth an ion propelled craft.