Exponential Hit Points

Level	KXP	Effect
1	0.3	+1 hp
2	0.6	+4 hp
3	1.2	+9 hp
4	2.4	+16 hp
5	4.8	+25 hp
6	9.6	+36 hp
7	19.2	+49 hp
8	38.4	+64 hp
9	60	+81 hp
10	90	+100 hp
11	120	+121 hp
12	150	+144 hp
13	180	+169 hp
14	210	+196 hp
15	240	+225 hp
16	270	+256 hp
17	300	+289 hp
18	330	+324 hp
19	360	+361 hp
20	390	+400 hp
21	420	+441 hp
22	450	+484 hp
23	480	+529 hp
24	510	+576 hp
25	540	+625 hp
26	570	+676 hp
27	600	+729 hp
28	630	+784 hp
29	660	+841 hp
30	690	+900 hp
31	720	+961 hp
32	750	+1024 hp
33	780	+1089 hp
34	810	+1156 hp
35	840	+1225 hp
36	870	+1296 hp

Each level you take in this overwrites the previous levels bonus to hp.