Supply reminds of crycoin it did pretty well when it first hit the exchanges.

Please do not worry, and let me quess OCMINER shut down stratum when supply reach ~20000 coins.  

Coin supply now 17k, when the block height will be 2000, supply will be much more when 20.7k coins.
Halving means division by 2 not 1.5. (26/2=13, 26/1.5=17.33).
Another 200 blocks after 600 give 2310,666666666667 coins.

56*200/1+56*200/2+56*200/3+56*200/4+56*200/5+56*200/6+56*200/7+56*200/8+56*200/9+56*200/10=32804.4444444
32.8k total pow coins.

I'm not sure PoS will start before pow ends. OP didn't gave the PoS start block...

What a good coin, I want to exchange quickly to sell it.  

any exchange?

There's nothing to worry about.
555th blocks:
http://107.170.240.91:3001/tx/934bde6365d36fa23ac0ddf7457735ef5b43f29df616f089daafeb6cc51089cc
http://107.170.240.91:3001/tx/7a864c5b42e6bbe621159547a6069c42ab889e982577258405fc10da4840ea8b
the block at first link didn't generate any coins so it's not an accepted block most likely it's orphan or smal bug on the explorer.
Probably bug on explorer.

What?

The chain doesn't accept PoW blocks beyond block 2000.....

Exactly.

Edit: While we're at it, PoS starts @ block 2000:

https://github.com/M1xProject/M1Project/blob/master/src/main.cpp#L2174

Very unlikely. Even if there is no weight @  block 2000  (again - very unlikely), the chain would start moving again as soon as there is (enough) weight.

PS: Block 2000 might also be a PoW block (the only block which can be either PoW or PoS).