private static void addFourFactors(long[] primes, List<Long> set) {
		for (int i = 1; i < primes.length && primes[i]*primes[i+1]*primes[i+2]*primes[i+3] <= limit; i++) {
			System.out.println(i + "four");
			long p1 = primes[i];
			for (int j = i+1; j < primes.length && primes[i]*primes[j]*primes[j+1]*primes[j+2] <= limit; j++) {
				System.out.println(i + " " + j + " four");
				long p2 = primes[j];
				for (int k = j+1; k < primes.length && p1*p2*primes[k]*primes[k+1] <= limit; k++) {
					long p3 = primes[k];
					for (int k2 = k+1; k2 < primes.length && p1*p2*p3*primes[k2] <= limit; k2++) {
						long p4 = primes[k2];
						long n = p1*p2*p3*p4;
						
						if ((n-1) % (n-(p1-1)*(p2-1)*(p3-1)*(p4-1)) == 0) {
							set.add(n);
						}					
					}
				}
			}
		}
	}