50000 Ruth-Aaron pairs

This 5000 Ruth-Aaron-pairs addition to my compilation (50000 factored pairs @ 6.3 MB) arrived much faster than my previous updates, because two days of the calculation were done on the new, much faster iMac. From now on, therefore, I'll update only when I have collected another 10000 pairs. My current aim for the compilation is ~150000 pairs (up to ~175 billion) @ ~20 MB.