Or you use the calculation in the datasheet OR you use something like...
http://www.picbasic.co.uk/forum/showthread.php?t=4994

OR you may prefer PBP do the math for you.
DEFINE HSER_BAUD 2400

This said, if you use PBP HSER_BAUD, you'll never know if the maths choose the best err % for you... one reason why i did that calc.

Unfortunately i doubt it will work at 20KHz... but 20MHZ yes...

I'm sure it's a typo mistake... just kidding you a bit