[Formula](http://formula.s21g.com/) is the service for embedding and sharing images of mathematical expression on your blog easily. Recently, the service corresponded to embedding by BBCode. For example, following BBCode is generated to be embedded. pre>> [url=http://formula.s21g.com/?f(x)%3D%5Cint_0%5E%7Bx%7Dg(t)%5C,dt][img]http://formula.s21g.com/?f(x)%3D%5Cint_0%5E%7Bx%7Dg(t)%5C,dt.png[/img][/url] <<-- So that you can use it for bulletin boards which are capable to interpret BBCode such as phpBB.