About EQ Editor
EQ Editor is an app for iPad that lets you create math equations and export them in PDF, MathML or HTML formats. The iTunes page for the app is here. The current version is 3.0 or later and it requires iOS 7. The official website: http://www.eqeditor.com/ has more information on the current version. Previous versions (which used iOS 6.0 or earlier) have been retired and are no longer available for download.
There is also freeware EQ Reader app that let’s you view saved MathML and TeX files and export image versions of them. The iTunes page for that is here.
You can contact the app writer through email: support–at–eqeditor–dot–com or by commenting on this site.
There used to be a universal version of the app called EQ Editor Lite as well as two other apps, EQ Notebook and EQ Writer. These are currently retired, though some of their features may come back in some form in the future.