conseq([X,Y|L], X, Y).
conseq([_|L], X, Y) :- conseq(L, X, Y).
mapNext(Code, [], []).
mapNext(Code, [X|L], [Y|LRes]) :- conseq(Code, X, Y), mapNext(Code, L, LRes).
?- string_codes(' 1U40ckjGEpdeil5xyde9STilbf237wzCKJoOdeilNILstnPMmQXYahVRgDAHuvrBFWZ1 ', Code),
string_codes('123', L),
mapNext(Code, L, X),
write(X).
Prolog