WinPFGW 3.7.10:
2^219021-3553 is 3-PRP! (26.7908s+0.0001s)
2^368946-3623 is 3-PRP! (77.9765s+0.0008s)
2^353344-3693 is 3-PRP! (72.7349s+0.0006s)

To be completed...