Even patenting a formula's application is becoming more restricted. In Australia and the US, the two relevant tests seem to be whether the formula does something a human can't, and whether the formula is used to 'improve' the operations of a computer or machine (e.g. if it made your hard drive faster or controlled a robotic arm).

I had to look into this regarding an algorithm we're building and whether it's patentable. If your formula is a mere scheme or method implemented in a computer, it's likely to be rejected. The following links add detail:

http://www.fisheradamskelly.com.au/2015/12/full-federal-cour...

https://en.wikipedia.org/wiki/Alice_Corp._v._CLS_Bank_Intern...

http://www.ipwatchdog.com/2016/05/13/federal-circuit-says-so...