I figured out how to implement Calculator/Arithmetician.
>make it a magic DPS Job
>make the weapon an abacus
>give it Cup of Life and Soulbind but change what they do, make these the main mechanics the Job is centered around
>Cup of Life is an AOE party buff that increases healing potency just a bit and increases magic damage dealt
>CoL applies in stacks of five, each recast resets the stack, one stack falls off every few seconds
>Soulbind is an AOE DoT
>also applies in stacks and decreases over time
>both Cup of Life and Soulbind are rather weak, but the amount of stacks when used together can give varying results
>casting a buff before each attack via 3, 4, 5 or Prime allows the next spell to increase potency dramatically depending on what the total added number of stacks for CoL and SB is
>3, 4, 5 and Prime are all OCD instants with fast recharges
>normal spells from other Jobs such as Holy, Firaga, etc are used but have an addendum on them similar to RDM for example something like "Calculated Holy" or "Calculated Thunder"