Suddenly, I can type (almost) anything in latex, e.g. \$a_n\$ becomes $a_n$. Fancy!
Many thanks for Peter Jipsen the folks who developed ASCIIMathML, which serves as the basis of LaTeXMathML by Douglas R. Woodall. Examples showing what is possible with LatexMathML can be found here. This is an indispensable tool!
The nice thing is that MathML is scaleable: