WinPFGW 3.7.10:
2^282609-4069 is 3-PRP! (47.0846s+0.0004s)
2^391261-4131 is 3-PRP! (91.1812s+0.0008s)
2^495935-4117 is 3-PRP! (143.0264s+0.0010s)

To be completed...