what iLVL is required to have each # of sockets?

So I know it is
1/2 sockets=any iLVL.
3=?
4=?
5=35 iLVL
6=50 iLVL

But I would very much like to know what item level is required for 3 and 4 sockets. Anyone have that info?

i know not all of it applies, its a copy/paste :)

Item level (not to be confused with the level requirement of an item) is what determines how many sockets a piece of gear can have.

You can find item level, in game, by picking up the item you want (selecting the item so your cursor grabs it), and typing “/itemlevel” in chat. You will then see feedback in the chat window telling you your item’s level.

Below are the item level requirements needed for sockets:
• Item level 1: 1-2 sockets
• Item level 10: 3 sockets
• Item level 28: 4 sockets
• Item level 35: 5 sockets
• Item level 50: 6 sockets
Note: If the item can roll the sockets, it is possible to link all of those sockets

Not all items can have 6 sockets, some items can have no sockets, below is a list of items with how many sockets they can have:
• Chest or 2h weapons: up to 6 sockets
• Helm, boots, or gloves: up to 4 sockets
• 1h weapons or shields: up to 3 sockets
• Quivers, jewelry, belt, or flasks: 0 sockets

If you’re having issues getting sockets, linking sockets, or changing socket colors, keep trying, random is random, it make 2 orbs, it may take 2,000. Remember though, DEX based gear is biased towards green sockets, STR based gear is biased towards red sockets, and INT based gear is biased towards blue sockets. That doesn’t mean that your INT gear won’t roll a red socket, or even a green. But if you’re trying to get R-R-R-G-B on your INT based gear, be prepared to spend A TON of orbs. You might be better off finding or trading for it rather than crafting it.

I think one unique chest doesn't have any sockets at all.