DOMAINS
list = integer*
PREDICATES
genl1(integer, integer, list).
nondeterm ins_in_pos(integer, list, integer, list).
CLAUSES
genl1(N2,N2,[]):-!.
genl1(N1,N2,[N1|L]):-N1<N2, N=N1+3, genl1(N,N2,L).
ins_in_pos(_,[],_,[]).
ins_in_pos(X,T,0,[X|T]) :- !.
ins_in_pos(X,[H|T],N,[H|Q]) :- N1=N-1, ins_in_pos(X,T,N1,Q).
GOAL
L8=[3, 6, 9, 12, 15, 18], nl, genl1(3,21,L), write(L), nl,
write("X= "), readint(X), nl,
write("Give me position "), readint(T), nl,
ins_in_pos(X, L, T, L1), write(L1), nl.