I'm trying to write a function `f`.

example:

     f /@ Range[0, 52]
    
     (* ==> {A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,
       AA,AB,AC,AD,AE,AF,AG,AH,AI,AJ,AK,AL,AM,AN,AO,AP,AQ,AR,AS,AT,AU,AV,AW,AX,AY,AZ,BA} *)
    
    f /@ (10^Range[8])
    
    (* ==> {K,CW,ALM,NTQ,EQXE,BDWGO,UVXWK,HJUNYW} *)

How I do it?