DouKaku?

import std.stdio;

struct HammingNumbers {
    static bool isHammingNumber(uint n) {
        static bool[uint] memo;
        
        if(n == 1) return true;
        if(auto p = n in memo) return *p;
        
        if(n % 2 == 0)
            return memo[n] = isHammingNumber(n / 2);
        if(n % 3 == 0)
            return memo[n] = isHammingNumber(n / 3);
        if(n % 5 == 0)
            return memo[n] = isHammingNumber(n / 5);
        return memo[n] = false;
    }
    
    static int opApply(int delegate(ref const(size_t), ref const(uint)) dg) {
        size_t i = 0;
        uint n = 1;
        while(true) {
            if(isHammingNumber(n)) {
                if(auto result = dg(i, n))
                    return result;
                i++;
            }
            n++;
        }
    }
}

void main(){
    foreach(i, n; HammingNumbers) {
        if(i == 100) break;
        writeln(i, ": ", n);
    }
}