I'm studying in university F#, and looked a bit on the internet but couldn't find a nice program to code in F#. Any suggestions?
F# Software Foundation is a great resource to start with.
Here is an excerpt from Using F# on Mac OSX:
What should I use to edit my code?
Some editors have specific support for F#, either builtin or through addons provided by the F# community:
We recommend Xamarin Studio or MonoDevelop with the F# AddIn for MonoDevelop.
Emacs. There is an F# mode for Emacs that extends Emacs with syntax highlighting for F#, support for working with F# Interactive and also automatic indentation.
VIM
SublimeText
While the first two options have the most up-to-date support, you can also use F# Interactive via command line and use the editor you feel the most comfortable with.