ok, what is up with the psionics progresion?

[bobthe6th]

Data:
level/total pp/pp gaind that level/pp gaind over last level/pp over level
1 2 2 2 2
2 6 4 2 3
3 11 5 1 3 2/3
4 17 6 1 4 1/4
5 25 8 2 5
6 35 10 2 5 5/6
7 46 11 1 6 4/7
8 58 12 1 7 1/4
9 72 14 2 8
10 88 16 2 8 8/10
11 106 18 2 9 7/11
12 126 20 2 10 1/2
13 147 21 1 11 4/13
14 170 23 2 12 6/14
15 195 25 2 13
16 221 26 1 13 13/16
17 250 29 3 14 12/17
18 280 30 1 14 8/18
19 311 31 1 16 17/19
20 343 32 1 17 3/20

the hell is with the progression?
it goes up at a near random interval, with no apparent rime or reason...
any one have an explanation?

[Starbuck_II]

Data:
level/total pp/pp gaind that level/pp gaind over last level/pp over level
1 2 2 2 2
2 6 4 2 3
3 11 5 1 3 2/3
4 17 6 1 4 1/4
5 25 8 2 5
6 35 10 2 5 5/6
7 46 11 1 6 4/7
8 58 12 1 7 1/4
9 72 14 2 8
10 88 16 2 8 8/10
11 106 18 2 9 7/11
12 126 20 2 10 1/2
13 147 21 1 11 4/13
14 170 23 2 12 6/14
15 195 25 2 13
16 221 26 1 13 13/16
17 250 29 3 14 12/17
18 280 30 1 14 8/18
19 311 31 1 16 17/19
20 343 32 1 17 3/20

the hell is with the progression?
it goes up at a near random interval, with no apparent rime or reason...
any one have an explanation?

Actually, it goes up at X+1 for awhile, goes X+2, then back to X+1.
2+4=6.
6+5=11
11+6=17
17+8=25 (okay , now it is X=2)
25 + 10=35
35+11=46 (back to X+1)
46+12=58
58+13=72
Etc

[bobthe6th]

and then 2 for 4 levels, then 1 for a level then 2, then 1 for a level then 3 for a level, then ones all the way out...

just levels 1-8 set a pattern, then 9-20 broke it... I was wondering why?

[ericgrau]

It's quadratic:
PP = 0.8422 * level^2 + 0.2221 * level + 2.2675
is within 1 power point for almost all levels.

The second term never gets higher than 4.5 so the dominate term is easily the first term while the rest is a minor adjustment. With that in mind I found it's also pretty close to:

PP = 0.86 * level^2 + 2

So the number of PP you gain each level increases by about 1.72. When you round that off it might look a little funky but it's a fairly close pattern. At least within 1 or 2 PP. "Add 1-5/8 to the amount you get each level (starting at 0)" also fit closely and any slight variation off of that does not fit so I bet 1-5/8 is somewhere in WotC's real numbers. I dunno if or why they vary it by a point or two but the curve is a really tight fit so there was some kind of method involved.