4digits to 3 with permuted numbers

Hi

I would like ask is how can I actually generate the result as below :

From 4 digits to 3 digits permuted numbers
e.g : 1234 (user enter this)

Generated numbers :
123
124
134
234

What we want is use the number posted by user, and we will use the number to arrange to 3 digit numbers in any possible ways as above. Repeated permuted numbers will only display once. Please advise.

Thank you.

Why would you want to do that? Homework?

I am trying to build a function to generate an output that I need to analyze a calculation. Hope gurus can help. Thanks

http://tagarga.com/blok/on/070910