sumJ(N, N, R, R, I)   :- !.
sumJ(N, N1, R, R1, I) :- N2 is N1 + 1
                       , R2 is R1 + I + N2 * I
                       , sumJ(N, N2, R, R2, I).

prodI(N, N, R, R)   :- !.
prodI(N, N1, R, R1) :- N2 is N1 + 1
                     , sumJ(N, 0, RS, 0, N2)
                     , R2 is R1 * RS
                     , prodI(N, N2, R, R2).

Y(N) :- prodI(N, 0, R, 1), WRITE(R).