So I was inspired by the new PGMMENU function. Eventually I want a better function plotter, but first I decided to implement sums, products, and function tables. It works a lot like the built in INTEG function. For tables, the result is a matrix. If the function returns multiple values, then they are all put in the matrix -- up to 4 of them in reverse order. For the sum & product, only the last return value from the function is used. It also has an option to take the ln of returned function values. Anyhow, have fun:
https://richmit.github.io/hp42/pgmforfun.html
EDIT: You need free42 v3 -- so use the beta firmware recently posted.