On behalf of Aabhisjek Porwal
1*4 = 4 (1+2)*4^2 = 3*16 = 48 (1+2+3)*4^3 = 6*64 = 384 (1+2+3+4)*4^4 = 10*256 = 2560 Similarly (1+2+3+4+5)*4^5 = 15*1024 = 15360