The Instramental Jazz Theme...

I know that the main theme for the show with the trumpets and trombones is supposed to be untitled but i heard something incredibly similar on the radio the other day. If you can think of what the song could be or have a download link to the actual theme could you please post it. The Instrumental section was about halfway through the song i heard. I've spent ages looking for it because the music in this show is some of the best i ever heard.