These are non-palindromic strobogrammatic primes and they have all been certified. No more terms up to 8700. Primality proof for the largest (a "gigantic" prime): PFGW Version 20041001.Win_Stable (v1.2 RC1b) [FFT v23.8] Primality testing 10^5345*(66161819199+10^(5345+10))+1 [N-1, Brillhart-Lehmer-Selfridge] Running N-1 test using base 3 Calling Brillhart-Lehmer-Selfridge with factored part 34.91% 10^5345*(66161819199+10^(5345+10))+1 is prime! (15.1367s+0.0109s)