It's easy to calculate the number of CFLs needed. Let's say the number of square feet of your seedling room is 10' x 12'.
The number of CFLs needed is:
10' x 12' x 1/4" = 120 square feet 1 cubic foot of seedlings = 240 seeds, so the number of CFLs needed is: 240 x 1/4" = 60 square feet So you'll need at least 60 square feet of CFLs to cover the seedlings.
If you're talking about seedlings (like lettuce) and not plants, the answer is two per plant. For example, I have 2-4 seedlings per plant in a 1 gallon pot. In the case of seedlings, they're usually grown in flats with two per flat. They can also be grown in individual pots, but that's more of an exception than a rule.