" as opposed to making many for loops"
Why would you use loops for this?
%x: a vector of numbers
x = 1:5;
%n: number of elements to pick (with repetetition) from x. n must be less than or equal to numel(x)
n = 4;
assert(n < numel(x), 'n can''t be greater than numel(x)')
combs = cell(1, n);
[combs{:}] = ndgrid(x);
combs = reshape(cat(n+1, combs{:}), [], n); %a numel(x)^n X n matrix of combinations
