[SOLVED] unique combination formula

Can anyone help!!!!.

I am trying to work out a formula for calculating unique combinations of items in a store e.g. 4 bottles of wine - select any 3 for £10.

This throws up a problem as for example if we name them 1,2,3 , the unique combinations are :

111 , 112 , 113 , 114 , 221 , 222 , 223 , 224 , 331 , 332 , 333 , 334

441 , 442 , 443 , 444 , 123 , 234 , 124 , 134

I need to ignore duplicates as 112 = 121 = 211 , 234 = 324 = 432 etc.

I would like to increase the number of items from 4 to say 10 and work out all combinations with a formula rather then by hand.

This is probably a breeze for you maths folks but it has had me scratching my head for a while !!!!

Thanks,

Barry.