PRP in base 79 and 83

For (39^n-37^n)/2, I found hitherto:
(39^1879-37^1879)/2
(39^2017-37^2017)/2
(39^3067-37^3067)/2
(39^4909-37^4909)/2
(39^9349-37^9349)/2

To be completed...