4th edition Dungeons & Dragons had a standard party size of 5 players. I can't seem to find an equivalent definition of what the standard party size is in 5th edition. The tables in the DMG mention adjusting encounters if there are less than 4 or more than 5 players, but doesn't seem to make a difference between 4 and 5.
Is there anything in the rules, errata, or sage advice defining what the standard party size in 5th edition is? Are the official adventures designed for 4 or 5 characters?