walk.prolog

step(0, []).
step(1,[1]).
step(2,[2]).
step(3,[3]).

step(N,[H|T]) :-
    N > 0,
    member(H, [1,2,3]),
    Remaining is N - H,
    Remaining > 0,
    step(Remaining, T).


count_steps(N, S) :-
    bagof(X, step(N, X), B),
    length(B, S).


print_table(Max) :-
    findall(_,(
        between(0, Max, N),
        count_steps(N, S),
        write((N,S)), nl
    ),_).