ised is a command-line tool for generating number sequences and
arithmetic evaluation. Unlike big gui-based software (e.g. Mathematica,
Derive, Matlab, Octave,...) it is intended for use in shell scripting,
together with gnu core utilities.

Its main advantage is that all functions are generalized to operate
on one-dimensional arrays. It can be used for loop indexing (much
like seq), line-by-line arithmetic processing of files, floating
point math for shells that don't support it natively, or interactively,
as extended calculator.