Product of elements in an array

I have an array as such (3 5 7 11), I want to find out the unique multiples of these elements i.e.

1) product of pairwise elements -- 15, 21, 33, 35, 55, 77

2) product of three elements -- 105, 385, 231

3) product of four elements -- 1055.

I am currently confused as to how to go about it in an efficient way so that when I extend it to larger number of elements in the array, I don't explode my memory and kill my computer. Any help would be greatly appreciated.

Thanks

Answer 1

[Matt J]

For example,

>> x=[3 5 7 11];
>> prod(nchoosek(x,3),2)

ans =

   105
   165
   231
   385