[Spaceships] simply fuel math...

[Anthony]

If you want

Tanks	eTanks
1	1.03
2	2.11
3	3.25
4	4.46
5	5.75
6	7.13
7	8.62
8	10.22
9	11.96
10	13.86
11	15.97
12	18.33
13	21.00
14	24.08
15	27.73
16	32.19
17	37.94
18	46.05
19	59.91

The formula in the second case is -20 * ln( 1 - 0.05* nTanks ).