Did M1 executive produce M2 and M3 and executive produce a prequel of M0
SELECT count(*) WHERE {
?x0 ns:film.film.sequel M0 .
M1 ns:film.producer.films_executive_produced ?x0 .
M1 ns:film.producer.films_executive_produced M2 .
M1 ns:film.producer.films_executive_produced M3
}