Selected strengths of Esheet from the web page:
The example sheet has formulas as follows:
+sum(range(1,y+0,x+-1,y+0))/sum(range(1,y+-1,x+-1,y+-1)) =(/ (sum (range 1 y (- x 1) y)) (sum (range 1 1 (- x 1) 1))) +mean(range(x+0,y+-2,x+0,y+-1))
A note on ComparativeEmacsology, also from the web page: Esheet runs under both Emacs and XEmacs. The XEmacs support is older, more reliable, and has a few added features (e.g. mouse support), but both work for most purposes.