Welcome to SWI-Prolog (threaded, 64 bits, version 8.0.3) SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software. Please run ?- license. for legal details. For online help and background, visit http://www.swi-prolog.org For built-in help, use ?- help(Topic). or ?- apropos(Word). ?- consult(crypto_rpg). true. ?- display_problems(10). numbers = {2,5,9,2,5} and goal = 6 numbers = {0,2,2,9,4} and goal = 0 numbers = {9,1,5,3,4} and goal = 8 numbers = {9,2,4,0,6} and goal = 8 numbers = {3,5,2,7,2} and goal = 4 numbers = {4,6,3,6,4} and goal = 5 numbers = {5,6,3,6,0} and goal = 4 numbers = {1,4,5,7,0} and goal = 4 numbers = {4,6,7,8,4} and goal = 3 numbers = {9,8,9,9,2} and goal = 2 true. ?- exit.