Respuesta :

Well,

This could be an arithmetic sequence.
1 + 2 = 3
3 + 3 = 6
6 + 4 = 10
10 + 5 = 15
15 + 6 = 21
...

This could also be a geometric sequence.
1*3=3
3*2=6
6*1=6
6*0=0
0*-1=0
0*(anything)=0
...