Not actually related to CRUS, but still interesting:
Primes for form 172*3^n+1
Code:
"0"
2
4
22
25
34
44
49
54
57
114
142
265
328
360
453
520
764
1070
2200
3424
12614
These are all primes n<25000.
Going deeper, at some point.
Thank you Karsten for missed prime at n=49, now fixed.