expand (1+t)(1+t+t^2)(1+t+t^2+t^3)(1+t+t^2+t^3+t^4)(1+t+t^2+t^3+t^4+t^5)

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.