$ pl
Welcome to SWI-Prolog (Multi-threaded, Version 5.6.24)
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For help, use ?- help(Topic). or ?- apropos(Word).

?- ['crypto.pro'].
%  combosets.pro compiled 0.00 sec, 7,448 bytes
% crypto.pro compiled 0.00 sec, 10,912 bytes

Yes
?- crypto(1,2,3,4,5,15,Solution).

Solution = ex(ex(ex(1, +, 2), +, 4), +, ex(5, +, 3)) ;

Solution = ex(ex(3, +, 4), +, ex(5, +, ex(1, +, 2))) ;

Solution = ex(5, +, ex(ex(1, +, 2), +, ex(3, +, 4))) ;

Solution = ex(5, +, ex(3, +, ex(ex(1, +, 2), +, 4))) ;

Solution = ex(ex(1, +, 2), +, ex(5, +, ex(3, +, 4))) ;

Solution = ex(3, +, ex(5, +, ex(ex(1, +, 2), +, 4))) ;

Solution = ex(ex(ex(1, +, 2), -, 4), *, ex(5, *, 3)) ;

Solution = ex(ex(3, -, 4), *, ex(5, *, ex(1, +, 2))) ;

Solution = ex(ex(ex(1, +, 2), -, 4), /, ex(5, *, 3)) ;

Solution = ex(ex(3, -, 4), /, ex(5, *, ex(1, +, 2))) ;

Solution = ex(5, *, ex(ex(1, +, 2), *, ex(3, -, 4))) 

Yes
?- crypto(1,1,1,1,1,5,Solution).

Solution = ex(ex(1, +, 1), +, ex(1, +, ex(1, +, 1))) ;

Solution = ex(ex(1, +, 1), +, ex(1, +, ex(1, +, 1))) ;

Solution = ex(1, +, ex(ex(1, +, 1), +, ex(1, +, 1))) ;

Solution = ex(1, +, ex(ex(1, +, 1), +, ex(1, +, 1))) ;

Solution = ex(1, +, ex(ex(1, +, 1), *, ex(1, +, 1))) ;

Solution = ex(1, +, ex(ex(1, +, 1), *, ex(1, +, 1))) ;

Solution = ex(ex(1, +, 1), +, ex(1, +, ex(1, +, 1))) ;

Solution = ex(ex(1, +, 1), +, ex(1, +, ex(1, +, 1))) ;

Solution = ex(ex(1, +, 1), +, ex(1, +, ex(1, +, 1))) ;

Solution = ex(ex(1, +, 1), +, ex(1, +, ex(1, +, 1))) ;

Solution = ex(1, +, ex(ex(1, +, 1), +, ex(1, +, 1))) ;

Solution = ex(1, +, ex(ex(1, +, 1), +, ex(1, +, 1))) ;

Solution = ex(1, +, ex(ex(1, +, 1), *, ex(1, +, 1))) ;

Solution = ex(1, +, ex(ex(1, +, 1), *, ex(1, +, 1))) ;

Solution = ex(ex(1, +, 1), +, ex(1, +, ex(1, +, 1))) ;

Solution = ex(ex(1, +, 1), +, ex(1, +, ex(1, +, 1))) ;

Solution = ex(ex(1, +, ex(1, +, 1)), +, ex(1, +, 1)) ;

Solution = ex(1, +, ex(1, +, ex(1, +, ex(1, +, 1)))) ;

Solution = ex(1, +, ex(1, +, ex(1, +, ex(1, +, 1)))) 

Yes
?- crypto(3,7,8,5,8,2,Solution).

Solution = ex(ex(3, +, 7), /, ex(8, -, ex(8, +, 5))) ;

Solution = ex(ex(8, *, 5), /, ex(8, *, ex(3, +, 7))) ;

Solution = ex(8, /, ex(ex(3, +, 7), /, ex(8, *, 5))) ;

Solution = ex(ex(3, +, 7), /, ex(8, /, ex(8, *, 5))) ;

Solution = ex(ex(3, +, 7), /, ex(8, -, ex(8, -, 5))) ;

Solution = ex(ex(3, +, 7), /, ex(8, +, ex(8, -, 5))) ;

Solution = ex(ex(8, -, 8), +, ex(5, /, ex(3, +, 7))) ;

Solution = ex(ex(8, -, 8), -, ex(5, /, ex(3, +, 7))) ;

Solution = ex(5, /, ex(ex(3, +, 7), +, ex(8, -, 8))) ;

Solution = ex(5, /, ex(ex(3, +, 7), -, ex(8, -, 8))) 

Yes
?-