// Solving the knapsack problem: given a number like 151 (the knapsack), fill it up with items here primes
// until it is full. Which items do you have to take

knapsack := function(Q, t)
    R := [IntegerRing() | x : x in Q | x le t];
    if &+R lt t then 
        return [ ];
    elif t in R then 
        return [t];
    else
        for x in R do
            RR := Exclude(R, x);
            s := $$(RR, t - x);
            if not IsEmpty(s) then
                return Append(s, x);
            end if;
        end for;
        return [ ];
    end if;
end function;

primes := [ p : p in [1..100] | IsPrime(p) ];
k := knapsack(primes, 151);
k, &+k;