WinPFGW 3.6.5:
2^204323-2221 is 3-PRP! (85.3881s+0.0008s)
2^208343-2221 is 3-PRP! (71.7658s+0.0019s)
2^214799-2221 is 3-PRP! (86.0294s+0.0020s)

To be completed...