Sleeping through night/night feedings

lwil2011

My son is 5 weeks old and we are feeding him 4-5oz formula every 3-4hrs. He is usually a good sleeper and will put himself to sleep when we lay him in his bassinet. When can I try and let him sleep through the night? I seem to always wake him up for his 3-4am feeding, but think sometimes he will sleep longer? Is it ok to just let him sleep?