question: Did M1 executive produce M2 and produce a film 's prequel and sequel
query: SELECT count(*) WHERE {
  ?x0 ns:film.film.prequel ?x1 .
  ?x0 ns:film.film.sequel ?x1 .
  ?x1 a ns:film.film .
  M1 ns:film.producer.films_executive_produced M2 .
  M1 ns:film.producer.film|ns:film.production_company.films ?x0
  }