2,4,4,0,16,()
2,4,2^2,4-4,4^2,(0-4)
1,4,12,28,55,()
1*1,2*2,3*4,4*7,5*11
1*1,2*(1+1),3*(2+2),4(3+4),55*(4+7),(6*(5+11))