WinPFGW 3.4.0:
2^377222+93679 is 3-PRP! (238.1015s+0.0001s)
2^375537+4847 is 3-PRP! (237.7939s+0.0028s)
2^256398+23299 is 3-PRP! (110.1036s+0.0028s)
2^255517+56387 is 3-PRP! (109.6466s+0.0026s)

To be completed...