Here's another that looks even better. There seems to be some "magic" with a three-tooth difference in front chain rings.

25... 47... 1.71
25... 50... 1.73
22... 47... 1.76
22... 50... 1.79
19... 47... 1.82
19... 50... 1.85
17... 47... 1.87
17... 50... 1.90
15... 47... 1.93
15... 50... 1.95
13... 47... 1.99
13... 50... 2.02