these are icons from http://www.wolfram.co.uk (the creators of Mathematica). i just removed the background and made it transparent.
the package contains an icon for the application itself and a mimetype for kde (including a file icon) in various resolutions.
to install, just extract the archive and copy the 'icons' directory to /usr/share (or wherever your other kde icons are). do the same for the 'mimelnk' dir.
i have an special authorisation from Wolfram Research, Inc. to distrubute these icons as they are provided here. _only_i_ am allowed to provide these icons _only_here_ on www.kde-look.org. please only use them for you personally.