=IF(C4=1,LEFT(A4,C4*4),IF(C4=2,LEFT(A4,C4*4),IF(C4=3,LEFT(A4,C4*4),IF(C4=4,LEFT(A4,C4*4),""))))
=IF(C4=1,LEFT(A4,4),IF(C4=2,LEFT(A4,8),IF(C4=3,LEFT(A4,12),IF(C4=4,LEFT(A4,16),""))))
=LEFT(A3,(INDEX(C3,{1,2,3,4,5})-1)*4)
=if(c4=1,"",if(c4=2,left(a4,4),if(c4=3,left(a4,8),if(c4=4,left(a4,12),if(c4=5,left(a4,16),"")))))
=LEFT(A1,(INDEX(C3,{1,2,3,4,5})-1)*4)